Definition of "rocket engine" []

• A reaction engine that contains all the substances necessary for its operation and is not dependent on substances such as atmospheric oxygen, drawn from the surrounding medium, and thus is capable of operating in outer space. Also called rocket motor. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "On August 8, 1955, just an instant before Joe Walker was to be dropped in the X-1A, an explosion within its rocket engine rocked the B-29."
• "Then, just as he was being dropped at altitude above Hidden Hills north of Death Valley across the Nevada line, his rocket engine did not ignite."