/ Dictionary / Index A ATPase: Meaning and Definition of Find definitions for: ATPase Pronunciation: (ā'tē'pē'ās, -āz), [key] — n. Biochem. adenosine triphosphatase: any of several enzymes that catalyze the hydrolysis of ATP to ADP and phosphate. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ATP atrabilious Related Content Daily Word Quiz: belligerent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language