n.
1) to conduct, make; launch an ~
2) a discreet; exhaustive, thorough; official ~
3) an ~ about (to make inquiries about a matter)
4) an ~ into (an official ~ into the incident was launched) USAGE NOTE: The noun ~ can mean 'question' or 'investigation'. In BE , the spelling enquiry is often recommended for the meaning 'question' -- an enquiry about her health. Compare -- an official ~ into the incident.