epoch

noun

ep·​och ˈe-pək 

ˈe-ˌpäk,

US also and British usually

ˈē-ˌpäk 

1

a

: an event or a time marked by an event that begins a new period or development

b

: a memorable event or date

2

a

: an extended period of time usually characterized by a distinctive development or by a memorable series of events

b

: a division of geologic time less than a period and greater than an age

3

: an instant of time or a date selected as a point of reference (as in astronomy)

Did you know?

Epoch comes to us, via Medieval Latin, from Greek epochē, meaning "cessation" or "fixed point." "Epochē," in turn, comes from the Greek verb epechein, meaning "to pause" or "to hold back." When "epoch" was first borrowed into English, it referred to the fixed point used to mark the beginning of a system of chronology. That sense is now obsolete, but today "epoch" is used in some fields (such as astronomy) with the meaning "an instant of time or a date selected as a point of reference." The "an event or a time that begins a new period or development" sense first appeared in print in the early 17th century, and "epoch" has been applied to defining moments or periods of time ever since.

Synonyms

• age
• day
• era
• period
• time

Choose the Right Synonym for epoch

period, epoch, era, age mean a division of time.

period may designate an extent of time of any length.

periods of economic prosperity

epoch applies to a period begun or set off by some significant or striking quality, change, or series of events.

the steam engine marked a new epoch in industry

era suggests a period of history marked by a new or distinct order of things.

the era of global communications

age is used frequently of a fairly definite period dominated by a prominent figure or feature.

the age of Samuel Johnson

Examples of epoch in a Sentence

The Civil War era was an epoch in 19th-century U.S. history.

The development of the steam engine marked an important epoch in the history of industry.

Recent Examples on the Web

During the Eocene epoch (roughly 33.9 million to 56 million years ago), oceans also warmed, and it’s often used as an analogue for what’s happening today. —Carlyn Kranking, Smithsonian Magazine, 17 Sep. 2024

But many now believe this long epoch is drawing to a close. —G. John Ikenberry, Foreign Affairs, 1 Nov. 2022

For three years, as brutal fighting raged up and down the Korean peninsula, the two sides gradually felt each other out and tacitly settled on rules of the road for the new epoch. —Gideon Rose, Foreign Affairs, 25 Apr. 2022

Last week that debate ended — temporarily at least — with a ruling from the International Commission on Stratigraphy (ICS) that rejected calls to declare the official state of the Anthropocene and the end of the Holocene epoch that has defined the planet's past 11,700 years. —Rafi Schwartz, theweek, 15 Mar. 2024

Word History

Etymology

Medieval Latin epocha, from Greek epochē cessation, fixed point, from epechein to pause, hold back, from epi- + echein to hold — more at scheme entry 1

First Known Use

1614, in the meaning defined at sense 1a

Phrases Containing epoch

• epoch-making

Podcast

Get Word of the Day delivered to your inbox!

Kids Definition

epoch

noun

ep·​och ˈep-ək  -ˌäk 

 also  ˈē-ˌpäk

1

: an event or a time that begins a new period of development

2

: a memorable event, date, or period

3

: a division of geologic time less than a period and greater than an age

epochal

-əl

adjective

epochally

-ə-lē

adverb