What does coeternal mean?
Coeternal is a formal adjective meaning equally eternal with something else — that is, having neither beginning nor end alongside another entity. Its natural habitat is theology and philosophy: Christian doctrine holds that the Son and the Holy Spirit are coeternal with the Father, a claim central to the Nicene Creed's rejection of the idea that the Son was created at some point in time. Beyond doctrine, writers may use it more loosely for things regarded as coexisting through an indefinitely vast span, such as two philosophical principles said to be coeternal. The word nearly always takes the preposition 'with' and carries a solemn, elevated register; it belongs to scholarly and liturgical prose rather than casual speech. Derived from Latin roots meaning 'together' and 'age-long', it also yields the rarer noun coeternity. For readers encountering dense theological or metaphysical texts, coeternal is a precise term worth knowing.
adjectiveExisting or lasting eternally alongside something else; equally eternal with another thing. Most often used in theology to describe persons of the Trinity as being eternal together.
- Equally eternal with something else; having existed for all time together with another entity (chiefly theological).
- By extension, lasting or coexisting throughout an indefinitely long period alongside something else.
"In Nicene theology, the Son is coeternal with the Father, having no beginning in time."
"The creed affirms that the Spirit is coeternal with the Father and the Son."
"Some philosophers describe matter and God as coeternal principles of the universe."
When early Christians needed a word to insist that the Son was not created but had always existed alongside the Father, they reached for 'coeternal' — and the word has carried that weight ever since.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of coeternal
Coeternal derives from Latin, combining the prefix co- ('together, jointly') with aeternalis ('eternal'), from aeternus ('age-long, everlasting'), itself rooted in aevum, 'age'. English adopted the word in late medieval and early modern religious writing, where it served debates over the Trinity and the nature of divine persons. It shares its root with the far more common words eternal and eternity, as well as the rare literary adjective sempiternal.
Related word forms
How coeternal is actually used
A formal, learned word found chiefly in theology, philosophy, and academic writing; rare in everyday conversation. It almost always appears with the preposition 'with', naming the entity with which something shares eternity.
Easily confused with coeternal
Coeval means originating or living at the same time or era, while coeternal means enduring eternally together without beginning or end.