/ Dictionary / Index S sixty-sixth: Meaning and Definition of Find definitions for: six•ty-sixth Pronunciation: (siks'tē-siksth'), [key] — adj. next after the sixty-fifth; being the ordinal number for 66. being one of 66 equal parts. —n. a sixty-sixth part, esp. of one (). the sixty-sixth member of a series. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sixty-six sixty-third Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language