/ Dictionary / Index Y yesternight: Meaning and Definition of Find definitions for: yes•ter•night Pronunciation: (yes'tur-nīt'), [key] — Archaic. Archaic. —n. last night. —adv. during last night. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. yestern yesternoon Related Content Daily Word Quiz: kiln Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language