Turbofan engine
A type of gas turbine engine that has a set of lengthened blades on the low-pressure compressor or low-pressure turbine. Air moved by these special blades bypasses the core engine and produces between 30% and 75% of the total thrust.
Aviation Maintenance Technician Handbook — Powerplant, p. G-29
Also defined in 1 more source
A fanlike turbojet engine designed to create additional thrust by diverting a secondary airflow around the combustion chamber.