Ramjet and Reaction engine

Ramjet noun - A simple type of jet engine; must be launched at high speed.

Reaction engine and ramjet are semantically related in gas airplane engine topic. In some cases you can use "Reaction engine" instead a noun "Ramjet".

Reaction engine noun - A jet or rocket engine based on a form of aerodynamic propulsion in which the vehicle emits a high-speed stream.

Ramjet and reaction engine are semantically related in gas airplane engine topic. You can use "Ramjet" instead a noun phrase "Reaction engine".