/ Dictionary / Index P planimeter: Meaning and Definition of Find definitions for: pla•nim•e•ter Pronunciation: (plu-nim'i-tur), [key] — n. an instrument for measuring mechanically the area of plane figures. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: planimeter (Thesaurus) planigraph planimetry Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language