/ Dictionary / Index M marginalia: Meaning and Definition of Find definitions for: mar•gi•na•li•a Pronunciation: (mär"ju-nā'lē-u, -nāl'yu), [key] — n.pl. marginal notes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: marginalia (Thesaurus) marginal cost marginalize Related Content Daily Word Quiz: bungled Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language