/ Dictionary / Index C cosh: Meaning and Definition of Find definitions for: cosh Pronunciation: (kosh), [key] — Chiefly Brit. Slang. Chiefly Brit. Slang. —n. a blackjack; bludgeon. —v.t. to hit on the head with a cosh. cosh Pronunciation: (kosh), [key] — n. Math. hyperbolic cosine. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: cosh (Thesaurus) Cosgrave cosher Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language