noun ep·och \ˈe-pək, ˈe-ˌpäk, US also and British usually ˈē-ˌpäk\

Definition of epoch

  1. 1a :  an event or a time marked by an event that begins a new period or developmentb :  a memorable event or date

  2. 2a :  an extended period of time usually characterized by a distinctive development or by a memorable series of eventsb :  a division of geologic time less than a period and greater than an age

  3. 3 :  an instant of time or a date selected as a point of reference (as in astronomy)

epoch was our Word of the Day on 01/13/2009. Hear the podcast!

Examples of epoch in a sentence

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

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

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.

Origin and Etymology of epoch

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

First Known Use: 1614

Synonym Discussion of 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

EPOCH Defined for English Language Learners


noun ep·och \ˈe-pək, ˈe-ˌpäk, US also and British usually ˈē-ˌpäk\

Definition of epoch for English Language Learners

  • : a period of time that is very important in history

EPOCH Defined for Kids


noun ep·och \ˈe-pək\

Definition of epoch for Students

  1. :  a period that is important or memorable

Seen and Heard

What made you want to look up epoch? Please tell us where you read or heard it (including the quote, if possible).


to cast off or become cast off

Get Word of the Day daily email!


Take a 3-minute break and test your skills!

Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.