/ Dictionary / Index H haystack: Meaning and Definition of Find definitions for: hay•stack Pronunciation: (hā'stak"), [key] — n. a stack of hay with a conical or ridged top, built up in the mowed field so as to prevent the accumulation of moisture and promote drying. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: haystack (Thesaurus) hay shock Hayti Related Content Daily Word Quiz: blanch Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language