/ Dictionary / Index H holy cow: Meaning and Definition of Find definitions for: ho'ly cow' Pronunciation: [key] — Slang. Slang. (used to express bewilderment, surprise, or astonishment.) Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Holy Communion Holy Cross Related Content Daily Word Quiz: simian Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language