Bedeutung von “oath” — Learner’s Dictionary

oath

noun us uk /əʊθ/

[ C ] a formal promise:

an oath of allegiance
They refused to take an oath of (= to promise) loyalty to the king.
under oath

If someone is under oath, they have promised to tell the truth in a law court:

He denied under oath that he was involved in the crime.

(Definition von “oath” aus dem Cambridge Learner's Dictionary © Cambridge University Press)