/ Dictionary / Index R rheobase: Meaning and Definition of Find definitions for: rhe•o•base Pronunciation: (rē'u-bās"), [key] — n. Physiol. the minimum electric current required to excite a given nerve or muscle. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rheo- rheology Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language