/ Dictionary / Index P prothoracic gland: Meaning and Definition of Find definitions for: prothorac'ic gland" Pronunciation: [key] either of a pair of endocrine glands in the anterior thorax of some insects, functioning to promote the series of molts from hatching to adulthood. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. prothonotary warbler prothorax Related Content Daily Word Quiz: exemplary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language