conservation of mass: Meaning and Definition of

conserva'tion of mass'

Pronunciation: [key]
— Physics. Physics.
  1. the principle that in any closed system subjected to no external forces, the mass is constant irrespective of its changes in form; the principle that matter cannot be created or destroyed. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.