/ Dictionary / Index H hydrotheca: Meaning and Definition of Find definitions for: hy•dro•the•ca Pronunciation: (hī"dru-thē'ku), [key] — pl. -cae the part of the perisarc covering a hydranth. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hydrotaxis hydrotherapeutics 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