/ Dictionary / Index A acus: Meaning and Definition of Find definitions for: a•cus Pronunciation: (ā'kus), [key] — pl. a•cus. a needle, esp. one used in a surgical operation. aculeus (def. 1). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. acupuncturist acusector Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language