/ Dictionary / Index A apx.: Meaning and Definition of Find definitions for: apx. Pronunciation: [key] appendix. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Apus apyrase Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language