GRE TOEFL infinitesimal Definition Extremely small; tiny, often too small to measure. Example "The chance of winning the lottery is infinitesimal." Sign in to save GRE Quiz → TOEFL Quiz → ← infinite infinity → Study tips featuring "infinitesimal" Write GRE Words Into Your Own Sentences TOEFL Academic Vocabulary: Study by Topic Related words GRE swill GRE taper GRE testy GRE abacus SAT abase GRE abash GRE abate GRE abbreviate GRE abbreviation SAT abdicate SAT abdomen GRE abduct