Jet: A collimated stream, spurt or flow of liquid or gas from a pressurized container, an engine, etc. The 'jet' in 'turbojet' refers to the stream of hot gas

Jet: A collimated stream, spurt or flow of liquid or gas from a pressurized container, an engine, etc. The 'jet' in 'turbojet' refers to the stream of hot gas coming out of the engine. The 'turbo' in 'turbojet' refers to the turbine. Not all turbine engines are jet engines, and strictly speaking not all jet engines are turbine engines (though by convention 'jet engine' is taken to mean an air breathing turbine engine specifically, excluding rocket engines which also use jets of hot gas for thrust..) This naming convention is also broken by ramjet and scramjet engines, which breath air and produce jets, but do not have turbines.