/ Dictionary / Index H horsetail agaric: Meaning and Definition of Find definitions for: horse'tail ag'aric Pronunciation: [key] the shaggy-mane. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. horse tail horsetail tree Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language