SAT GRE TOEFL momentous Definition Of great importance or significance. Example "The discovery of penicillin was a momentous event in medical history." Sign in to save SAT Quiz → GRE Quiz → TOEFL Quiz → ← momentary momentum → Study tips featuring "momentous" Let the Argument Reveal Unfamiliar Word Meanings Group Words Together by Emotional Tone Map Each Word Into a Connected Network Related words SAT antonym SAT abase SAT abdicate SAT abdomen SAT abduction SAT abet SAT abeyance SAT abject SAT abjure SAT ablution SAT abnegate SAT abnormal