/ Dictionary / Index E equilibrium valve: Meaning and Definition of Find definitions for: equilib'rium valve" Pronunciation: [key] (in a reciprocating engine) a valve opening a passage from one end of a cylinder to the other to equalize pressure upon both faces of the piston. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. equilibrium price equimolecular Related Content Daily Word Quiz: crockery Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language