1. a question asked to obtain information
Usage: British English spelling; American English typically uses 'inquiry'
2. an investigation or examination into something
Usage: British English spelling; American English typically uses 'inquiry'

Examples

• She made an enquiry about the job opening at the company.
• The police launched an enquiry into the missing documents.
• I received several enquiries from interested customers.
• The government ordered a public enquiry into the accident.
• He sent an email enquiry asking for more details about the product.