/ Dictionary / Index P postmeridian: Meaning and Definition of Find definitions for: post•me•rid•i•an Pronunciation: (pōst"mu-rid'ē-un), [key] — adj. of or pertaining to the afternoon. occurring after noon: a postmeridian lull. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: postmeridian (Thesaurus) postmaster general post meridiem Related Content Daily Word Quiz: penchant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language