/ Dictionary / Index P plano-concave: Meaning and Definition of Find definitions for: pla•no-con•cave Pronunciation: (plā"nō-kon'kāv, -kon-kāv'), [key] — adj. Optics. pertaining to or noting a lens that is plane on one side and concave on the other. See diag. under Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: plano-concave (Thesaurus) planoblast plano-convex 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