/ Dictionary / Index G geoisotherm: Meaning and Definition of Find definitions for: ge•o•i•so•therm Pronunciation: ( jē"ō-ī'su-thûrm"), [key] — n. isogeotherm. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. geoid geol. Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language