/ Dictionary / Index T theca: Meaning and Definition of Find definitions for: the•ca Pronunciation: (thē'ku), [key] — pl. -cae a case or receptacle. a sac, cell, or capsule. a sporangium. a case or sheath enclosing an organ, structure, etc., as the horny covering of an insect pupa. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: theca (Thesaurus) Thebes thecate Related Content Daily Word Quiz: blithesome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language