sem·​pi·​ter·​nal ˌsem-pi-ˈtər-nᵊl How to pronounce sempiternal (audio)
: of never-ending duration : eternal
sempiternally adverb

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Despite their similarities, sempiternal and eternal come from different roots. Sempiternal is derived from the Late Latin sempiternalis and ultimately from semper, Latin for "always." (You may recognize semper as a key element in the motto of the U.S. Marine Corps: semper fidelis, meaning "always faithful.") Eternal, on the other hand, is derived, by way of Middle French and Middle English, from the Late Latin aeternalis and ultimately from aevum, Latin for "age" or "eternity." Sempiternal is much less common than eternal, but some writers have found it useful. 19th-century American writer Ralph Waldo Emerson, for example, wrote, "The one thing which we seek with insatiable desire is to forget ourselves, … to lose our sempiternal memory, and to do something without knowing how or why…."

Examples of sempiternal in a Sentence

Recent Examples on the Web But law, and especially the sempiternal distinction between right and wrong, is never predicated on contracts or consent. Daniel J. Mahoney, National Review, 20 June 2019

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'sempiternal.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English, from Late Latin sempiternalis, from Latin sempiternus, from semper ever, always, from sem- one, same (akin to Old Norse samr same) + per through — more at same, for

First Known Use

15th century, in the meaning defined above

Time Traveler
The first known use of sempiternal was in the 15th century


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Cite this Entry

“Sempiternal.” Dictionary, Merriam-Webster, Accessed 20 Jun. 2024.

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