/ Dictionary / Index H holopneustic: Meaning and Definition of Find definitions for: hol•op•neus•tic Pronunciation: (hol"up-n'stik, -ny'-, hō"lup-), [key] — adj. having all the spiracles open, as the tracheal systems of most insects. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. holoplankton holosericeous Related Content Daily Word Quiz: impetuous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language