oath
A solemn promise or declaration, often invoking a divine witness.
Etymology
From Old English āþ, from Proto-Germanic *aiþaz. This traces to PIE *h₃eyt- meaning "to swear an oath." Oath-taking was central to Indo-European society — treaties, legal proceedings, and warrior bonds were all sealed by oaths invoking the gods.
The Journey: *h₃eyt- → oath
*h₃eyt-
*aiþaz
āþ
oath
Cognates Across Languages
These words in other languages descend from the same PIE root *h₃eyt-. They are not borrowings but independent inheritances from a common ancestor.
| Language | Word |
|---|---|
| Greek | oîtos (fate) |
| Latin | (none direct) |
| Gothic | aiþs |
| Old Irish | óeth (oath) |
| Old Norse | eiðr |
| Old High German | eid |
Did You Know?
In Germanic law, oath-breaking was one of the worst crimes — an oath-breaker (Old English āþbreca) was an outlaw. The modern legal phrase "on oath" and "sworn testimony" preserve this ancient Indo-European institution.
This word descends from the Proto-Indo-European root *h₃eyt-. See the full root page for descendant trees, sound law references, and scholarly discussion.