If you have ever written “I have an enquiry” and wondered whether it should be “I have an inquiry,” you are not alone.
These two words look almost identical, sound alike, and usually mean the same thing. The difference is mainly regional spelling and usage preference, rather than a completely different meaning.
The situation becomes slightly more interesting in British English, where enquiry is commonly used for an ordinary request for information, while inquiry can be preferred in some contexts involving a formal investigation.
In American English, inquiry is the standard spelling for both meanings. Cambridge describes enquiry as another spelling of inquiry, while Merriam-Webster identifies enquiry as chiefly a British spelling.
So, which should you use? That depends largely on where you are writing and what kind of context you mean.
Quick Answer
Enquiry and inquiry are both correct nouns meaning a question, request for information, or investigation.
- Enquiry is chiefly associated with British English, especially for a general request for information.
- Inquiry is standard in American English and is also widely used in British English.
- In British usage, inquiry is sometimes preferred for a formal investigation, although the distinction is not absolute.
- If you are writing for an American audience, choose inquiry. For British English, enquiry is a natural choice for an ordinary question or request.
Enquiry vs Inquiry: At a Glance
| Feature | Enquiry | Inquiry |
|---|---|---|
| Basic meaning | A question, request for information, or investigation | A question, request for information, or investigation |
| Part of speech | Noun | Noun |
| Pronunciation | /ɪnˈkwaɪəri/ | /ɪnˈkwaɪəri/ |
| Main English variety | British English | American English and British English |
| General question | Very common in British English | Standard in American English |
| Request for information | Common in British English | Common in American English |
| Formal investigation | Used, but inquiry is often preferred in some British contexts | Very common |
| Verb | enquire | inquire |
| Plural | enquiries | inquiries |
| Tone | Neutral; often British | Neutral; standard internationally |
| Formal or informal? | Can be either | Can be either |
| American English | Less common | Preferred |
| British English | Common | Also correct |
| Is one wrong? | No | No |
| Best choice in US writing | Usually avoid | Use inquiry |
| Best choice in UK writing | Natural for general requests | Natural, especially for formal investigations |
| Example | “I have an enquiry about my order.” | “I have an inquiry about my order.” |
Bottom line: The safest choice is not about “correct vs incorrect.” It is about regional convention and context.
What Does Enquiry Mean?
Enquiry is a noun meaning a question or request made to obtain information. It can also refer to an investigation.
It is especially common in British English.
For example:
“I sent an enquiry about the course fees.”
Here, enquiry simply means a request for information.
You might make an enquiry about:
- a product
- a service
- a price
- a booking
- a job
- a course
- opening hours
- availability
- delivery
- a company’s policies
Enquiry as a General Question
In British English, enquiry is very natural when someone wants information.
For example:
“We received several enquiries about the new membership plan.”
This means that several people asked for information about the plan.
Another example:
“If you have any further enquiries, please contact our office.”
This is a common type of wording in British business communication.
Enquiry in Professional Writing
British companies, schools, universities, government offices, and customer-service departments may use enquiry when referring to a customer’s or reader’s request for information.
For example:
“Thank you for your enquiry regarding our services.”
This sounds professional without being unnecessarily formal.
You might see:
- customer enquiries
- general enquiries
- sales enquiries
- media enquiries
- telephone enquiries
- product enquiries
- membership enquiries
The plural form is enquiries, not enquirys.
Enquiry in Everyday English
The word is not restricted to formal writing.
A British English speaker might say:
“I made an enquiry at the hotel.”
Or:
“I called the school with an enquiry about admissions.”
In American English, the same sentences would normally use inquiry.
The Verb Connected With Enquiry
The corresponding British spelling is enquire.
For example:
“I would like to enquire about the position.”
American English normally uses inquire:
“I would like to inquire about the position.”
The spelling relationship is therefore:
British: enquire → enquiry → enquiries
American: inquire → inquiry → inquiries
Merriam-Webster specifically describes enquire and enquiry as chiefly British spellings of inquire and inquiry.
What Does Inquiry Mean?
Inquiry is a noun with the same broad meanings: a question, request for information, or investigation.
It is the standard spelling in American English.
For example:
“I sent an inquiry about the position.”
This simply means:
“I asked for information about the position.”
Inquiry as a Request for Information
In American English, inquiry is the normal word for an information request.
You could write:
“We received an inquiry from a customer about the warranty.”
Or:
“Please direct all inquiries to the customer-service department.”
The word works perfectly well in:
- emails
- websites
- business letters
- customer service
- academic writing
- journalism
- everyday communication
Inquiry as an Investigation
Inquiry can also mean a systematic investigation into something.
For example:
“The committee launched an inquiry into the incident.”
This is more than someone casually asking a question. It suggests an organized attempt to discover facts.
You can therefore have:
- a government inquiry
- a police inquiry
- a formal inquiry
- an independent inquiry
- an official inquiry
- a public inquiry
- an academic inquiry
- an inquiry into a complaint
This meaning is especially important when discussing British English, because some British writers use inquiry to signal a formal investigation while reserving enquiry for a general request for information. However, this is a usage tendency, not an absolute grammar rule. Collins lists inquiry and enquiry as forms in British English and gives both “request for information” and “investigation” among the meanings.
Inquiry in American English
American English generally does not maintain a spelling distinction between the two meanings.
The same spelling works for both:
“I made an inquiry about the hotel.”
and:
“The government ordered an inquiry.”
That makes inquiry particularly straightforward if your audience is primarily American.
Why Do Enquiry and Inquiry Exist?
The two spellings are not unrelated words that happened to develop similar meanings. They are variant forms of the same word.
Their history is connected to the verb inquire, which ultimately traces back through French and Latin forms associated with asking or seeking information.
English has long developed spelling variations involving prefixes such as en- and in-. Over time, both enquire/enquiry and inquire/inquiry became established.
Modern dictionaries therefore do not generally treat enquiry as a misspelling of inquiry.
Cambridge’s British dictionary explicitly describes enquiry as another spelling of inquiry.
Merriam-Webster likewise labels enquire and enquiry as chiefly British spellings.
So if you see enquiry in a British document, it is not automatically an error.
Enquiry vs Inquiry in British English
This is where the comparison gets more interesting.
In British English, both spellings are used, but some writers make a practical distinction:
- enquiry → a general question or request for information
- inquiry → a formal investigation
For example:
“I made an enquiry about the train schedule.”
Here, someone simply wants information.
But:
“The government announced an inquiry into the accident.”
Here, inquiry can suggest an official or formal investigation.
This distinction is useful, but it should not be treated as a universal British-English rule.
Some British publications and organizations use inquiry for both meanings. Others use enquiry for general questions and inquiry for investigations. Collins, for example, recognizes both spellings in British English and gives both the information-request and investigation senses.
A UK government editorial style guide also lists inquiry/enquiry among alternative spellings and gives the practical distinction “inquiry (formal investigation)/enquiry (question).”
A Useful British-English Rule
If you are writing British English and want to make the distinction clear, you can use:
Enquiry = “I want to know something.”
Inquiry = “Someone is investigating something.”
For example:
“I made an enquiry about the application process.”
versus:
“An independent inquiry was established to investigate the allegations.”
This distinction is useful, especially in formal British writing.
But remember: British usage is not completely standardized around this distinction.
Enquiry vs Inquiry in American English
For American English, the decision is much easier:
Use inquiry.
Examples:
“I have a question about my account.”
→ “I have an inquiry about my account.”
“The company received hundreds of inquiries.”
“The committee conducted an inquiry.”
“Please send your inquiry to our support team.”
The spelling enquiry will generally look British or non-American to an American reader.
That does not make it inherently wrong. It simply does not match the usual American spelling convention.
Are Enquiry and Inquiry Interchangeable?
Usually, yes.
Both words can refer to a question, request for information, or investigation.
However, their regional preferences and contextual associations can differ.
Consider these sentences:
“Thank you for your enquiry.”
“Thank you for your inquiry.”
Both communicate essentially the same message.
The first sounds naturally British.
The second sounds naturally American and is also perfectly acceptable in British English.
The difference becomes more noticeable when you are writing for a specific audience.
If Your Audience Is British
Use enquiry for ordinary requests if you want conventional British wording.
For formal investigations, inquiry may be the clearer choice.
If Your Audience Is American
Use inquiry for both ordinary requests and investigations.
If Your Audience Is International
Inquiry is often the easiest spelling to standardize across an international audience, particularly if your content follows American or globally common business conventions.
However, consistency matters more than trying to create an artificial distinction.
Key Differences Between Enquiry and Inquiry
Here are the most important points to remember:
- Both words are correct.
- Enquiry is chiefly a British spelling.
- Inquiry is the standard American spelling.
- Both can mean a question or request for information.
- Both can refer to an investigation.
- British writers sometimes use enquiry for ordinary questions.
- British writers may use inquiry for formal investigations.
- That British distinction is a tendency, not an absolute rule.
- American English normally uses inquiry for both meanings.
- The corresponding verbs are enquire and inquire.
Is Enquiry More Formal Than Inquiry?
No.
Neither spelling is inherently more formal.
The apparent difference comes mainly from regional usage and context.
For example:
“Please contact us if you have any enquiries.”
This can sound formal because it is common in professional British correspondence, but the spelling itself does not make the sentence formal.
Likewise:
“Please contact us if you have any inquiries.”
is equally professional in American English.
Formal language depends more on word choice, sentence structure, tone, and context than on choosing enquiry over inquiry.
Grammar: How to Use Enquiry and Inquiry Correctly
Both words are countable nouns.
That means you can use:
- an enquiry
- an inquiry
- several enquiries
- several inquiries
- a further enquiry
- a formal inquiry
- numerous enquiries
- several inquiries
Singular Forms
Use an because both words begin with a vowel sound:
“I have an enquiry.”
“She made an inquiry.”
Plural Forms
The plural changes -y to -ies:
enquiry → enquiries
inquiry → inquiries
Do not write:
- enquiryes
- enquirys
- inquiry’s
- inquiryies
Possessive Forms
For one inquiry:
“The inquiry’s findings were published.”
For multiple inquiries:
“The inquiries’ findings were compared.”
The apostrophe belongs to the possessive construction, not to the plural itself.
Compare:
inquiries = more than one inquiry
inquiry’s = belonging to one inquiry
inquiries’ = belonging to multiple inquiries
Verb Forms: Enquire vs Inquire
The noun difference is closely connected to the verb difference.
British English
enquire
enquired
enquiring
enquirer
American English
inquire
inquired
inquiring
inquirer
Examples:
“I would like to enquire about your services.”
“I would like to inquire about your services.”
Both mean essentially the same thing.
Enquire About vs Enquire Into
There is a useful grammatical distinction here.
Enquire about usually means ask for information about something.
“She enquired about the course.”
Enquire into can mean investigate something.
“The committee will enquire into the complaint.”
The American equivalents are:
“She inquired about the course.”
“The committee will inquire into the complaint.”
The verb inquire can also mean to investigate, and Merriam-Webster specifically lists both asking for information and investigating among its meanings.
20+ Real-Life Examples of Enquiry and Inquiry
The easiest way to understand this distinction is to see how the words work in different situations.
1. Everyday Conversation
“I made an enquiry about the apartment.”
British English.
“I made an inquiry about the apartment.”
American English.
2. Customer Service
“Thank you for your enquiry. We will respond within two working days.”
Natural British business English.
3. American Customer Service
“Thank you for your inquiry. We will respond within two business days.”
Natural American English.
4. Email
“I am writing to make an enquiry about the position advertised on your website.”
A conventional British-English formulation.
5. American Email
“I am writing to make an inquiry about the position advertised on your website.”
Natural American spelling.
6. University
“The admissions office received several enquiries from international students.”
British spelling.
7. American University
“The admissions office received several inquiries from prospective students.”
American spelling.
8. Business
“Our sales team handles all product enquiries.”
A natural British formulation.
9. American Business
“Our sales team handles all product inquiries.”
A natural American formulation.
10. Formal Investigation
“The minister announced an inquiry into the incident.”
This wording is particularly natural when referring to a formal investigation.
11. Police Investigation
“The police are continuing their inquiry.”
Here, inquiry means an investigation rather than a simple question.
12. Academic Writing
“The study represents an important inquiry into the causes of language change.”
Here, inquiry refers to systematic intellectual investigation.
13. Research
“Scientific inquiry depends on evidence and careful analysis.”
This is a standard academic use of inquiry.
14. School
“The students conducted an inquiry into local environmental issues.”
The word describes an organized investigation.
15. Social Media
“I sent the company an enquiry about the missing order.”
British English.
16. Text Message
“Made an enquiry about the tickets. Will let you know.”
Informal British usage.
17. American Text Message
“I sent them an inquiry about the tickets.”
Informal American usage.
18. Hotel
“We received an enquiry about room availability.”
British English.
19. Hotel in the United States
“We received an inquiry about room availability.”
American English.
20. Job Application
“I would like to enquire whether the position is still available.”
British English.
21. American Job Application
“I would like to inquire whether the position is still available.”
American English.
22. Government
“An independent inquiry was established to examine the matter.”
Here, inquiry strongly suggests a formal investigation.
23. Newspaper
“The inquiry examined whether the regulations had been followed.”
The word refers to an investigation.
24. Website Contact Page
“For general enquiries, please contact our reception team.”
A particularly familiar British-English expression.
25. International Business
“For further inquiries, please contact our support team.”
This spelling is common in international and American-oriented business communication.
Common Mistakes With Enquiry and Inquiry
Mistake 1: Treating Enquiry as Incorrect
Incorrect assumption:
“Enquiry is a misspelling.”
That is not correct.
Better understanding:
“Enquiry is a chiefly British spelling of inquiry.”
Merriam-Webster explicitly identifies enquiry as a chiefly British spelling, and Cambridge treats it as another spelling of inquiry.
Mistake 2: Assuming Inquiry Is Only American
Incorrect assumption:
“British English uses enquiry, so inquiry is American English only.”
That is too simplistic.
Better:
British English uses both enquiry and inquiry.
The distinction between the two can depend on context, house style, and the writer’s preference.
Mistake 3: Using Enquiry in American Writing
This is not necessarily a grammatical error, but it may look out of place in American English.
Less natural for a US audience:
“Please send your enquiry to our support department.”
Preferred American version:
“Please send your inquiry to our support department.”
Mistake 4: Assuming Inquiry Always Means Investigation
Incorrect assumption:
“Inquiry can only mean a formal investigation.”
Not true.
An inquiry can simply be a question or request for information.
“I called with an inquiry about my order.”
There is no investigation here.
Mistake 5: Using the Wrong Plural
Wrong:
“We received several enquirys.”
Correct:
“We received several enquiries.”
Similarly:
Wrong:
“We received several inquiry.”
Correct:
“We received several inquiries.”
Mistake 6: Confusing Plural and Possessive Forms
Wrong:
“We received three inquiry’s.”
Correct:
“We received three inquiries.”
Remember:
-ies = plural
-‘s = singular possessive
Which Is More Common: Enquiry or Inquiry?
There is no single worldwide answer because English varies by region.
In American English, inquiry is the normal spelling.
In British English, both forms occur, with enquiry commonly used for ordinary requests for information and inquiry often appearing in formal-investigation contexts.
Collins lists enquiry as British English and inquiry as the American form when discussing the general “question” sense.
This is why you may encounter both spellings on English-language websites.
What About International English?
International organizations often choose one spelling according to their editorial style.
The most important rule for professional writing is:
Choose a convention and use it consistently.
If a company website uses British English throughout, suddenly switching from enquiries to inquiries can make the copy look inconsistent.
The same principle applies to:
- organisation/organization
- colour/color
- centre/center
- realise/realize
- travelling/traveling
Consistency is often more important than trying to declare one spelling universally correct.
Enquiry vs Inquiry in Business English
Business writing is one area where this distinction matters because companies often communicate with customers across different English-speaking regions.
British Business English
You may naturally see:
“Thank you for your enquiry.”
“For further enquiries, please contact us.”
“We are responding to your enquiry.”
“General enquiries should be directed to reception.”
These are all perfectly normal British formulations.
American Business English
You are more likely to see:
“Thank you for your inquiry.”
“For further inquiries, please contact us.”
“We are responding to your inquiry.”
“For general inquiries, contact our office.”
The difference is primarily spelling convention, not professionalism.
Enquiry vs Inquiry in Academic Writing
Academic English gives us another useful distinction.
Inquiry is particularly common when discussing intellectual investigation, research, or a structured search for knowledge.
Examples include:
“The research contributes to scientific inquiry.”
“The article examines the role of inquiry in education.”
“The project encourages independent inquiry.”
In British academic writing, enquiry may still occur when the meaning is simply a request or question, but inquiry is a strong choice when discussing investigation or intellectual exploration.
This also explains why phrases such as scientific inquiry, philosophical inquiry, and academic inquiry are normally written with inquiry.
Common Collocations
Learning common word combinations can make your English sound much more natural.
Common with Enquiry
- general enquiry
- customer enquiry
- sales enquiry
- product enquiry
- telephone enquiry
- further enquiry
- initial enquiry
- make an enquiry
- receive an enquiry
- respond to an enquiry
- deal with an enquiry
Examples:
“We received a customer enquiry this morning.”
“Please contact the office with any further enquiries.”
Common with Inquiry
- formal inquiry
- official inquiry
- public inquiry
- government inquiry
- police inquiry
- independent inquiry
- scientific inquiry
- academic inquiry
- parliamentary inquiry
- inquiry into
- line of inquiry
- make an inquiry
- conduct an inquiry
- launch an inquiry
Collins lists collocations such as formal inquiry, official inquiry, police inquiry, scientific inquiry, line of inquiry, and set up an inquiry.
Enquiry vs Inquiry: Which One Should You Use?
Use this simple decision process.
Use enquiry when:
- You are writing British English.
- You mean a general request for information.
- Your organization’s style guide prefers enquiry.
- You want conventional British wording such as “general enquiries.”
Use inquiry when:
- You are writing American English.
- You mean a formal investigation.
- You are discussing scientific, academic, or intellectual investigation.
- Your organization’s style guide specifies inquiry.
- You want one spelling that works naturally in American English for both major senses.
A Simple Decision Tree
Ask yourself three questions:
1. Am I writing for an American audience?
→ Use inquiry.
2. Am I writing British English and asking for information?
→ Enquiry is a natural choice.
3. Am I writing British English about a formal investigation?
→ Inquiry is often the clearer choice.
That covers most everyday situations.
Memory Tricks for Enquiry vs Inquiry
Here are several ways to remember the difference.
Memory Trick 1: E = England
Think:
E = Enquiry = England
This is not a rule of English grammar, but it is an easy memory aid for remembering the British spelling.
Memory Trick 2: I = International/American
Think:
I = Inquiry = the spelling used in American English
Again, this is simply a mnemonic, not an etymological rule.
Memory Trick 3: Question vs Investigation
For British English:
Enquiry → question
Inquiry → investigation
Imagine someone saying:
“I have an enquiry.”
They want an answer.
Then imagine:
“There is an inquiry.”
Something is being investigated.
Memory Trick 4: Remember the Verb
The noun follows the verb:
enquire → enquiry
inquire → inquiry
If you remember the verb spelling, the noun becomes much easier.
Enquiry vs Inquiry: US vs UK English
| Context | British English | American English |
|---|---|---|
| General question | enquiry / inquiry | inquiry |
| Request for information | enquiry / inquiry | inquiry |
| Formal investigation | inquiry commonly preferred in some contexts | inquiry |
| Verb meaning ask | enquire / inquire | inquire |
| Verb meaning investigate | enquire / inquire | inquire |
| General business email | enquiry is common | inquiry is standard |
| Plural of enquiry/inquiry | enquiries / inquiries | inquiries |
The key point is that British English permits more variation, while American English overwhelmingly favors inquiry.
What Do Dictionaries Say?
Modern dictionaries support the idea that these are legitimate variant forms rather than a simple “correct vs incorrect” pair.
Cambridge Dictionary identifies enquiry in British English as another spelling of inquiry.
Merriam-Webster describes enquiry as a chiefly British spelling of inquiry.
Collins Dictionary recognizes both inquiry and enquiry in British English and gives the words both the question/request and investigation senses.
This matters because it demonstrates that enquiry is not simply a spelling mistake.
Style Guides and House Style
Professional organizations may choose one form even when both are linguistically acceptable.
For example, a UK government editorial style guide lists inquiry/enquiry as alternative spellings and notes that British organizations may distinguish between inquiry for a formal investigation and enquiry for a question.
Other organizations may simply standardize on inquiry.
Therefore, if you are writing:
- a company website
- a government document
- a university publication
- a newspaper
- a legal document
- a technical manual
- marketing copy
check the organization’s house style first.
If there is a specified spelling, follow it consistently.
Does the Meaning Change?
Sometimes, depending on regional convention and context—but not always.
In the broadest sense, the words are synonyms.
For example:
“I sent an enquiry about the course.”
and:
“I sent an inquiry about the course.”
Both mean that you requested information.
But in some British usage, a distinction is made between:
enquiry = a request for information
and:
inquiry = a formal investigation
This distinction is useful, but it is not universal across all British speakers or publications.
So it is better to say:
The words can have the same meaning, but some British usage distinguishes them by context.
That is more accurate than claiming they always have different meanings.
Is “Enquiry” a British Spelling?
Yes.
Enquiry is chiefly associated with British English.
That does not mean every British writer uses it, however. Inquiry is also used in British English, particularly in contexts where the meaning is an investigation.
Merriam-Webster explicitly calls enquiry a chiefly British spelling, while Cambridge lists it as another spelling of inquiry in British English.
Is “Inquiry” an American Spelling?
Yes, and more than that.
Inquiry is the standard spelling in American English.
American writers generally use it whether they mean:
- a question
- a request for information
- an investigation
- academic investigation
- scientific investigation
For an American audience, inquiry is therefore the clear default.
Can You Use “Enquiry” in American English?
You can encounter it, but it is not the normal American spelling.
If you are deliberately writing British English, there is nothing wrong with using enquiry.
But if your goal is natural American English, choose:
inquiry
Likewise, use:
inquire
rather than:
enquire
Can You Use “Inquiry” in British English?
Yes.
This is an important point.
It would be misleading to tell British writers that inquiry is wrong.
British English uses inquiry, especially in contexts involving formal investigations, although it can also be used for ordinary requests for information. Collins explicitly recognizes inquiry and enquiry as British forms.
Is “Enquiry” More British Than “Inquiry”?
Generally, yes, for the spelling itself.
If you see:
“Please direct your enquiries to our office.”
the spelling strongly suggests British English.
If you see:
“Please direct your inquiries to our office.”
the spelling is natural in American English and also possible in British English.
So the regional signal is stronger for enquiry than for inquiry.
Frequently Asked Questions
Is enquiry or inquiry correct?
Both are correct. Enquiry is chiefly British, while inquiry is standard American and also used in British English. In British usage, inquiry may be preferred when referring to a formal investigation.
What is the difference between enquiry and inquiry?
The basic meanings overlap. Both can mean a question, request for information, or investigation. The main difference is regional spelling, with a possible additional distinction in British English between general enquiries and formal inquiries.
Should I use enquiry or inquiry in British English?
For a general request for information, enquiry is a natural British choice. For a formal investigation, inquiry is often preferred. However, both forms occur in British English.
Should I use inquiry or enquiry in American English?
Use inquiry. It is the standard American spelling for both a request for information and an investigation.
Is enquiry a British spelling?
Yes. Enquiry is chiefly a British spelling of inquiry. It is not simply an error or misspelling.
Is inquiry more formal than enquiry?
Not inherently. Inquiry can appear more formal because it is frequently used for investigations, but the spelling itself does not determine formality.
Is “make an enquiry” correct?
Yes. Make an enquiry is a standard British-English expression meaning to ask for information.
For American English, use:
“make an inquiry.”
What is the plural of enquiry?
The plural is enquiries.
For example:
“We received several enquiries.”
The American spelling is:
“We received several inquiries.”
What is the difference between enquire and inquire?
They are corresponding verb forms. Enquire is chiefly British, while inquire is standard American and also used in British English. Both can mean to ask for information or investigate.
Final Verdict
So, enquiry vs inquiry is not a battle between a correct word and an incorrect one.
Both are legitimate English words.
The best choice depends on your audience and context:
- 🇬🇧 British English + general request: enquiry
- 🇬🇧 British English + formal investigation: inquiry is often preferred
- 🇺🇸 American English + any ordinary use: inquiry
- 🌍 International writing: choose the spelling required by your organization’s style and remain consistent
If you are writing a British-English website, phrases such as “general enquiries,” “customer enquiries,” and “make an enquiry” are perfectly natural.
If you are writing American English, use “general inquiries,” “customer inquiries,” and “make an inquiry.”
The most important lesson is this:
Enquiry is not wrong, and inquiry is not exclusively American. They are variant spellings whose use depends largely on English variety, context, and house style.
When in doubt, identify your target audience first. British audience? Enquiry is a natural choice for a general request. American audience? Inquiry is the clear choice. Formal investigation? Inquiry is generally the safer term.
And once you choose a spelling, use it consistently throughout the document. That is the professional editor’s best practice.
Evan Bennett is a language enthusiast who writes simple, clear guides about word meanings, slang, phrases, and everyday expressions.
He helps readers understand modern language quickly with easy explanations and useful examples.