ˈepəkəl also ˈeˌpäk- sometimes (ˈ)ē|päk- or ˈepik- or ˈepēk- or ə̇|päk- or eˈpäk- adjective
1. : of or relating to an epoch
2.
a. : bringing about or marking the beginning of a new development or era
the epochal venture of Christopher Columbus — I.M.Price
b. : uniquely or highly significant (as in a historical development) : momentous
his fights to advance … democracy during his three epochal years in the assembly — C.G.Bowers
: unparalleled
the American delegates … have fallen for it out of their almost epochal dumbness — J.T.Flynn
• ep·och·al·ly -kəlē, -li adverb