Definition
An aircraft other than a public aircraft. In U.S. regulation, public aircraft generally means government-owned or government-operated aircraft used for non-commercial government purposes. Everything else — privately owned aircraft, commercial airliners, business jets, training aircraft, rental aircraft — falls under the civil aircraft category and is subject to FAA airworthiness, registration, and operating rules.
Plain English
Any aircraft that isn't a government or military aircraft. If it's owned and flown by a private person, a flight school, an airline, or a business, it's a civil aircraft.
Context Anchor
You may see this term in Federal Aviation Administration handbooks, rules, aircraft documents, and preflight discussions when the text is talking about aircraft operated under normal civilian aviation rules.
Derivation
From Latin civilis, meaning 'relating to citizens,' as opposed to military or government use. The same root gives us 'civilian.' In aviation, 'civil' carries that same sense: aircraft belonging to ordinary citizens and businesses rather than the state.
Why Pilots Care
Determines which FAA regulations and preflight standards apply to the flight.
Intuition Check
Civil does not mean polite or well-behaved here. It means the aircraft is operated in civilian aviation, not as a military aircraft or certain special government aircraft.
Example Sentence 1
Before flight, the pilot confirmed the required documents were on board, as regulations require for any civil aircraft.
Example Sentence 2
A student pilot may only fly civil aircraft under the supervision of an instructor.