KO

American  

[key-oh, key-oh, key-oh] / ˈkeɪˈoʊ, ˈkeɪˌoʊ, ˈkeɪˈoʊ /

Or K.O.,

noun

KO's plural

1. a knockout in boxing.

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verb (used with object)

KO'd, KO'ing

1. to knock unconscious, especially in a boxing match; knock out.

KO British  

/ ˈkeɪˈəʊ /

verb

1. a slang term for knock out See knockout

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noun

1. a slang term for knockout

Other Word Forms

Inflected Forms

noun

• KO's
  plural

Etymology

Origin of KO

First recorded in 1920–25; initial letters of knock out

Example Sentences

Coca-Cola’s KO 5.78%increase; green up pointing triangle new Chief Executive Henrique Braun has a magic number: 1.25.

From The Wall Street Journal • Apr. 28, 2026

During the past several years, Brush has suggested KO, UTZ and HSY in his stock newsletter, Brush Up on Stocks.

From MarketWatch • Feb. 7, 2026

"We got Justin the good look and KO got the rebound and put it back."

From Barron's • Nov. 12, 2025

American legend Marvin Hagler survived some vicious bouts, notably his 1985 war with Thomas Hearns, before retiring without a losing KO on his record.

From BBC • May 8, 2024

And you never want Daddy to go for the KO.

From "The Hate U Give" by Angie Thomas

Related Words

• beating
• blow
• breakdown
• collapse
• debacle
• destruction
• drubbing
• embarrassment
• failure
• killing
• loss
• massacre
• rout
• setback
• thrashing
• triumph