/ Dictionary / Index T twenty-fifth: Meaning and Definition of Find definitions for: twen•ty-fifth Pronunciation: (twen'tē-fifth', twun'-), [key] — adj. next after the twenty-fourth; being the ordinal number for 25. being one of 25 equal parts. —n. a twenty-fifth part, esp. of one (). the twenty-fifth member of a series. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: twenty-fifth (Thesaurus) twenty-eighth Twenty-fifth Amendment Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language