rhizoverbBeta
DictionarypropulsionForward driving force
noun

propulsion

pruh-PUL-shun/prəˈpʌlʃn/

The action or system of driving something forward.

The rocket's propulsion comes from gas expelled backward through its nozzle.

A small uncrewed rocket traveling nose-first to the right, with a clear exhaust plume streaming left from its rear nozzle, showing propulsion through backward-expelled gas.
Etymology
proLatinforward
+pulsLatinpush, drive
+ionLatinaction

The pieces describe pushing or driving forward. Although propulsion first meant expulsion or driving away in English, its current sense centers on the action, force, or system that produces forward movement.

In context

BBC Earth Science2:48
Things like non-rocket space drives, interstellar propulsion, and manipulating gravity, things like that.
Anti-Gravity: The Secret Space Race | Weird Science | Earth Science

More examples

  • The rocket loses propulsion when its engine shuts down.
  • Fish use their tails for propulsion through the water.
  • Engineers test a new propulsion system for the spacecraft.

Forms

propel verb — To drive or push something forward.

propulsive adjective — Providing force that drives something forward.

Similar words

thrust
The pushing force itself, rather than the whole driving system.
drive
Often refers to the mechanism that transmits power for movement.