Why is it called rocket engine?

A rocket engine is named for its mechanism of propulsion, which involves expelling mass at high speed to generate thrust, based on Newton's third law of motion: for every action, there is an equal and opposite reaction. Unlike traditional engines that rely on atmospheric oxygen, rocket engines carry both fuel and an oxidizer, allowing them to operate in the vacuum of space. This capability is essential for launching spacecraft and achieving high velocities necessary for orbital and interplanetary travel.