/ Dictionary / Index D duodecimal: Meaning and Definition of Find definitions for: du•o•dec•i•mal Pronunciation: (d"u-des'u-mul, dy"-), [key] — adj. pertaining to twelfths or to the number 12. proceeding by twelves. —n. one of a system of numbers based on the number 12. one of 12 equal parts. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: duodecimal (Thesaurus) duodecillion duodecimo Related Content Daily Word Quiz: pristine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language