oath

noun

ˈōth 

plural oaths ˈōt͟hz 

ˈōths

1

a(1)

: a solemn usually formal calling upon God or a deity to witness to the truth of what one says or to witness that one sincerely intends to do what one says

(2)

: a solemn attestation of the truth or inviolability of one's words

The witness took an oath to tell the truth in court.

b

: something (such as a promise) corroborated by an oath

They were required to swear an oath of loyalty.

took the oath of office

2

: an irreverent or careless use of a sacred name

broadly : swear word

He uttered an oath and stormed away.

Synonyms of oath

• promise
• vow
• pledge

Examples of oath in a Sentence

an oath to defend the nation

He uttered an oath and walked away.

Recent Examples on the Web

Implicit in that oath is to defend the country from foes, whether external or internal. —Chicago Tribune, Twin Cities, 17 Apr. 2026

Both of those events took place in 2016, well outside the statute of limitations, but prosecutors are probing whether Brennan committed perjury when testifying under oath about these events before Congress in 2023. —Sarah N. Lynch, CBS News, 17 Apr. 2026

Little glowing kiosks that accept cards, Apple Pay, cash, cryptocurrency or perhaps a solemn oath of eternal loyalty to Tri-Rail. —Yehiel Kyle Israel, Sun Sentinel, 15 Apr. 2026

But Republicans have made no effort to compel military commanders or members of the president's Cabinet to appear publicly and under oath answer questions from lawmakers. —Arkansas Online, 15 Apr. 2026

Word History

Etymology

Middle English ooth, from Old English āth; akin to Old High German eid oath, Middle Irish oeth

First Known Use

before the 12th century, in the meaning defined at sense 1a(1)

Phrases Containing oath

• Hippocratic oath
• oath of office
• on oath
• under oath

Rhymes for oath

• both
• doeth
• growth
• loath
• quoth
• sloth
• troth
• ingrowth
• outgrowth
• undergrowth

Kids Definition

oath

noun

ˈōth 

plural oaths ˈōt͟hz 

ˈōths

1

: a solemn appeal to God or to some deeply respected person or thing to witness to the truth of one's word or the sincerity of a promise

under oath to tell the truth

2

: a careless or improper use of a sacred name

also : swearword

Medical Definition

oath

see hippocratic oath

Legal Definition

oath

noun

1

: a solemn attestation of the truth of one's words or the sincerity of one's intentions

specifically : one accompanied by calling upon a deity as a witness

2

: a promise (as to perform official duties faithfully) corroborated by an oath compare perjury