/ Dictionary / Index T theta: Meaning and Definition of Find definitions for: the•ta Pronunciation: (thā'tu, thē'-), [key] — n. the eighth letter of the Greek alphabet (&THgr;, &thgr;). the consonant sound represented by this letter. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: theta (Thesaurus) Thessaly theta rhythm Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language