oath

American  

[ohth] / oʊθ /

noun

plural

oaths

1. a solemn appeal to a deity, or to some revered person or thing, to witness one's determination to speak the truth, to keep a promise, etc..

   to testify upon oath.

2. a statement or promise strengthened by such an appeal.

   Synonyms:

   pledge, vow

3. a formally affirmed statement or promise accepted as an equivalent of an appeal to a deity or to a revered person or thing; affirmation.

4. the form of words in which such a statement or promise is made.

5. an irreverent or blasphemous use of the name of God or anything sacred.

   Synonyms:

   profanity

6. any profane expression; curse; swear word.

   He slammed the door with a muttered oath.

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idioms

1. take an oath, to swear solemnly; vow.

oath British  

/ əʊθ /

noun

1. a solemn pronouncement to affirm the truth of a statement or to pledge a person to some course of action, often involving a sacred being or object as witness

2. the form of such a pronouncement

3. an irreverent or blasphemous expression, esp one involving the name of a deity; curse

4. 1. under the obligation of an oath

   2. law having sworn to tell the truth, usually with one's hand on the Bible

5. to declare formally with an oath or pledge, esp before giving evidence

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Etymology

Origin of oath

First recorded before 900; Middle English oth, Old English āth; cognate with Gothic aiths, Old Norse eidhr, German Eid

Explanation

An oath is a promise. If you want to borrow your brother's car, you may have to swear a solemn oath that you will bring it back unharmed. An oath is a solemn promise, sometimes made in front of a witness, or a vow in a court of law that you will tell the absolute truth. No matter what the circumstances are, swearing an oath is serious business. That's why it's odd that an oath can also be an angry outburst of obscene words. Your brother might mutter an oath under his breath and clench his fists angrily if you return his car to him with a broken side mirror.

Example Sentences

Last year, in a stunning court filing, Gonzalez Rogers wrote that an Apple executive "outright lied" under oath and referred the matter to the US Attorney for the Northern District of California.

From BBC • May 6, 2026

They can demand documents and can compel witnesses to testify under oath without counsel present while offering a one-sided version of the case to jurors.

From Slate • May 1, 2026

He took his oath with his hand on a book of poems by the city’s namesake, Quaker poet John Greenleaf Whittier, that belonged to the council’s sole remaining white person, Republican Cathy Warner.

From Los Angeles Times • May 1, 2026

Boyd had testified under oath in a deposition a year ago that he didn’t recall deleting anything on his phone.

From The Wall Street Journal • Apr. 5, 2026

Finally, Anthony and fourteen other women took the oath and had their names added to the official voter rolls.

From "Votes for Women!" by Winifred Conkling

Related Words

• affidavit
• deposition
• pledge
• testimony
• vow