Rocket engine and Thruster

Rocket engine noun - A jet engine containing its own propellant and driven by reaction propulsion.

Thruster and rocket engine are semantically related. In some cases you can replace term "Thruster" with "Rocket engine", this terms are similar.

Thruster noun - A small rocket engine that provides the thrust needed to maneuver a spacecraft.

Rocket engine and thruster are semantically related. You can use "Rocket engine" instead a noun "Thruster".