/ Dictionary / Index S semicentenary: Meaning and Definition of Find definitions for: sem•i•cen•ten•ar•y Pronunciation: (sem"ē-sen-ten'u-rē, -sen'tn-er"ē, sem"ī- or, esp. Brit., -sen-tē'nu-rē), [key] — pl. -ar•ies. semicentennial. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: semicentenary (Thesaurus) semibreve semicentennial Related Content Daily Word Quiz: pundit Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language