/ Dictionary / Index O offsider: Meaning and Definition of Find definitions for: off•sid•er Pronunciation: (ôf'sī'dur, of'-), [key] — n. Australian. an assistant or helper. a follower or supporter of a person or cause. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: offsider (Thesaurus) offside offspring Related Content Daily Word Quiz: blithesome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language