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

His son immediately became king and last week took an oath of allegiance to Norway’s constitution in parliament. — ABC News, 9 Sep. 2026

Ellen, however, is more concerned with Brian and Murtagh (Rory Alexander), who is also on the run with them, making it out alive than any oath. — Emlyn Travis, Entertainment Weekly, 8 Sep. 2026

Rather, the crisis of the Lincoln has illuminated a pattern of callousness and cruelty toward military personnel, people who have sworn an oath to support and defend the Constitution of the United States of America. — Andrea N. Goldstein, The Atlantic, 28 Aug. 2026

The new monarch took the oath of allegiance to the Constitution before the Storting. — Stefania Conrieri, Vanity Fair, 28 Aug. 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