/ Dictionary / Index P planoblast: Meaning and Definition of Find definitions for: plan•o•blast Pronunciation: (plan'u-blast"), [key] — n. Zool. the medusa of a hydroid. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. plano plano-concave Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language