/ Dictionary / Index I isopleth: Meaning and Definition of Find definitions for: i•so•pleth Pronunciation: (ī'su-pleth"), [key] — n. a line drawn on a map through all points having the same numerical value, as of a population figure or geographic measurement. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: isopleth (Thesaurus) isoplastic graft isopod Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language