Plain English Meaning
It is the FAA's stamp of approval on an aircraft design itself, saying 'this design is safe to build and fly.' Each individual aircraft built afterward must match that approved design.
Full Definition
An official FAA approval document certifying that a particular design of aircraft, engine, or propeller meets the airworthiness standards required for that category. It establishes the approved design — the specifications, limitations, and configurations — that every aircraft built to that design must conform to.
Context Anchor
Seen when learning how the FAA approves aircraft designs before those aircraft can be produced, sold, and operated legally.
Derivation
Type' here means a specific design or model — for example, the Cessna 172 'type.' A Type Certificate is therefore an official certificate covering a whole design, not a single aircraft.