/ Dictionary / Index P perimeter: Meaning and Definition of Find definitions for: pe•rim•e•ter Pronunciation: (pu-rim'i-tur), [key] — n. the border or outer boundary of a two-dimensional figure. the length of such a boundary. a line bounding or marking off an area. the outermost limits. a fortified boundary that protects a troop position. an instrument for determining the peripheral field of vision. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: perimeter (Thesaurus) perilymph perimorph Related Content Daily Word Quiz: morose Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language