What does the word propulsion mean?

Usage examples for propulsion

  1. Hence it results that when the body is cut in two, the hinder part continues to move forward under the propulsion of its numerous legs; and that when the chain of ganglia has been divided without severing the body, the hind limbs may be seen trying to propel the body in one direction while the fore limbs are trying to propel it in another. – Essays: Scientific, Political, & Speculative, Vol. I by Herbert Spencer
  2. Checking velocity soon enough, so close to the Moon, took all of the propulsion tube's power- so he just followed the comet down. – Comet's Burial by Raymond Zinke Gallun