Answer: epochal

AnswerCrossword Clue
EPOCHALMomentous
EPOCHALVery influential
EPOCHALHistorically significant
EPOCHALEarth-shattering
EPOCHALHighly significant
EPOCHALOf a historic interval
EPOCHALOf a time period
EPOCHALExtremely important
EPOCHALExtremely significant
EPOCHALOf a historic period
EPOCHALEra-defining
epochalof, pertaining to, or of the nature of an epoch
epochalpertaining to an epoch (an important period of time, also EPOCHA, ERA)
epochalextremely important, significant, or influential