oath

The word “oath” means a solemn formal promise, often invoking something sacred, to tell the truth or keep a commitment. In plain terms, a formal, serious promise (as in a courtroom or ceremony), or, less commonly, a swear word.

“Oath” is pronounced OHTH (/ˈoʊθ/ in IPA).

Here is “oath” used in a sentence: “The witness took an oath to tell the whole truth.”

Words with a similar meaning to “oath” include pledge, vow and avowal.

“Oath” is a noun.

The word “oath” comes from Old English. From Old English ath, from Proto-Germanic aithaz, meaning "oath".

“Oath” is a fairly common word in modern English, usually learned at around the B2 level.

“Oath” has 2 distinct senses listed in this dictionary. The most common is: a solemn formal promise, often invoking something sacred, to tell the truth or keep a commitment.

An oath is a solemn formal promise that often invokes something sacred, such as swearing on a holy book. An affirmation is a formal declaration with the same legal force but without any religious reference, offered by people who prefer not to swear by something sacred.

Both are solemn promises, but a vow is usually a personal pledge of commitment, such as wedding vows or a vow of silence. An oath tends to be a formal, often public promise to tell the truth or fulfill a duty, frequently sworn before others or invoking something sacred.

In its second sense, an oath is a curse word or swear word. This use comes from the way people once swore by sacred names in anger or surprise, so such exclamations became known as oaths, as in the phrase "muttering oaths."