ep·​och | \ ˈe-pək How to pronounce epoch (audio) , ˈe-ˌpäk, US also and British usually ˈē-ˌpäk How to pronounce epoch (audio) \

Definition of epoch

1a : an event or a time marked by an event that begins a new period or development
b : a memorable event or date
2a : 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)

Synonyms for epoch


Visit the Thesaurus for More 

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

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.

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 Much remains a mystery about the first billion years of the universe’s history, the epoch in which the cosmos emerged from its dark ages with the dawning of the earliest stars and galaxies. Charles Q. Choi, Scientific American, 10 May 2022 The fossil dates to the late Oligocene epoch and is believed to be 24 million to 28 million years old. Pam Kragen, San Diego Union-Tribune, 2 May 2022 The light from this epoch, now stretched to microwave wavelengths because of the universe’s subsequent expansion, is detectable as the all-pervading cosmic microwave background. Anil Ananthaswamy, Scientific American, 18 Apr. 2022 Jacob Mchangama’s history of free speech can feel rushed in its epoch-spanning opening chapters. Graham Hillard, National Review, 31 Mar. 2022 Those days were supposedly consigned to a shadowy epoch of the Berlin Wall, countless noirish thrillers and the daily proximity of nuclear Armageddon. Anchorage Daily News, 24 Feb. 2022 San Diego looked very different back in the Eocene epoch, from about 56 million to 34 million years ago. Raegan Scharfetter, Scientific American, 15 Mar. 2022 Those days were supposedly consigned to a shadowy epoch of the Berlin Wall, countless noirish thrillers and the daily proximity of nuclear Armageddon. Anchorage Daily News, 24 Feb. 2022 Earendel emitted its light remarkably close to the cosmic dawn - the epoch when the first stars ignited and galaxies began to form. Joel Achenbach, Anchorage Daily News, 30 Mar. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'epoch.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of epoch

1614, in the meaning defined at sense 1a

History and Etymology for epoch

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

Learn More About epoch

Listen to Our Podcast About epoch

Dictionary Entries Near epoch




See More Nearby Entries 

Statistics for epoch

Last Updated

20 May 2022

Cite this Entry

“Epoch.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/epoch. Accessed 24 May. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for epoch


ep·​och | \ ˈe-pək How to pronounce epoch (audio) \

Kids Definition of epoch

: a period that is important or memorable

More from Merriam-Webster on epoch

Nglish: Translation of epoch for Spanish Speakers

Britannica English: Translation of epoch for Arabic Speakers

Britannica.com: Encyclopedia article about epoch


Test Your Vocabulary

Which Word Does Not Belong?

  • one green toy robot amidst many red toy robots
  • Which of these words does not mean "nonsense"?
True or False

Test your knowledge - and maybe learn something along the way.

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!