Jet engine and Turbofan engine

Jet engine noun - A gas turbine produces a stream of hot gas that propels a jet plane by reaction propulsion.

Turbofan engine and jet engine are semantically related. In some cases you can replace phrase "Turbofan engine" with "Jet engine", this phrases are similar.

Turbofan engine noun - A jet engine in which a fan driven by a turbine provides extra air to the burner and gives extra thrust.

Jet engine and turbofan engine are semantically related. You can use "Jet engine" instead a noun phrase "Turbofan engine".