/ Dictionary / Index C conservation of linear momentum: Meaning and Definition of Find definitions for: conserva'tion of lin'ear momen'tum Pronunciation: [key] — Physics. Physics. the principle that the linear momentum of a system has constant magnitude and direction if the system is subjected to no external force. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. conservation of lepton number conservation of mass Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language