/ Dictionary / Index C Celticism: Meaning and Definition of Find definitions for: Celt•i•cism Pronunciation: (kel'tu-siz"um, sel'-), [key] — n. a Celtic custom or usage. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Celtic cross Celto- 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