/ Dictionary / Index H heat wave: Meaning and Definition of Find definitions for: heat' wave" Pronunciation: [key] an air mass of high temperature covering an extended area and moving relatively slowly. a period of abnormally hot and usually humid weather. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. heat-treat heaume Related Content Daily Word Quiz: acerbity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language