Plain English Meaning
It is the official approval system that confirms an aircraft (and its key parts) was built to an approved design, meets safety standards, and is allowed to fly.
Full Definition
The FAA process by which an aircraft, engine, propeller, or related product is formally certified as meeting approved design and safety standards and is therefore legal to operate. The governing rules are found in 14 CFR Part 21, which sets out the procedures for issuing type certificates, production certificates, and airworthiness certificates for aircraft and their major components.
Context Anchor
Seen in discussions of aircraft maintenance records, repairs, alterations, , and whether an aircraft may be returned to .