epochal

[ ep-uh-kuh l or, esp. British, ee-po- ]

/ ˈɛp ə kəl or, esp. British, ˈi pɒ- /

of, relating to, or of the nature of an epoch.

extremely important, significant, or influential.

Origin of epochal

First recorded in 1675–85; epoch + -al¹

ep·och·al·ly, adverb non·ep·och·al, adjective pre·ep·och·al, adjective un·ep·och·al, adjective

epizooty, epns, epo, epoch, epoch-making, epochal, epode, epoetin alfa, eponychia, eponychium, eponym

His deficiencies and self-doubts, amid his epochal mission of liberation, are precisely what make him interesting.

Meet Moses the Swashbuckling Israelite |James Romm |December 14, 2014 |DAILY BEAST
Physics—and, indeed, the rest of the world—stands at the cusp of an epochal change.

Must-Read College Novels: From “Lucky Jim” to “Pnin” |Sam Munson |August 13, 2012 |DAILY BEAST
But even his dying was epochal—everything about this amazing writer resonates.

Joseph Roth’s Letters Reveal a Great Forgotten Writer |Anthony Heilbut |February 10, 2012 |DAILY BEAST
In the grand scheme, this bill is not as significant as the epochal legislation of the 1930s and 1960s.

Overcoming the Fear Factor |Ted Widmer |March 21, 2010 |DAILY BEAST

Observe, then, that Davy made his epochal experiment of melting ice by friction when he was a youth of twenty.

A History of Science, Volume 3(of 5) |Henry Smith Williams
In the following year of 1871, Goodyear invented his welt shoe-sewing machine and Maddox made his epochal discovery.

Invention |Bradley A. Fiske
Not too wide, however, for there were certain ones who must keep track of all details regarding this epochal event.

The Broken Gate |Emerson Hough
To-day she was facing the first problem of her young life, epochal.

Parrot & Co. |Harold MacGrath
Coronado had made one of the epochal explorations of all history.

The Colonization of North America |Herbert Eugene Bolton