- a ritualistic declaration, typically based on an appeal to God or a god or to some revered person or object, that one will speak the truth, keep a promise, remain faithful, etc.
- the ritual form used in making such a declaration
- the thing promised or declared in this way
- the irreverent or profane use of the name of God or of a sacred thing to express anger or emphasize a statement
- a swearword; curse
Origin of oathMiddle English oth from Old English ath, akin to German eid, probably via Celtic from Indo-European an unverified form oitos (from source Old Irish ?eth) from base an unverified form ei-, to go (basic sense: uncertain or unknown; perhaps “to advance to take an oath”) from source year, Classical Latin ire, to go