• synonyms


[key-oh, key-oh; verb key-oh]Slang.
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noun, plural kay·os, verb, kay·oed, kay·o·ing.
  1. KO.

Origin of kayo

An Americanism dating back to 1920–25


or K.O., k.o., kay·o

[noun key-oh, key-oh; verb key-oh]Slang.
noun, plural KO's.
  1. a knockout in boxing.
verb (used with object), KO'd, KO'ing.
  1. to knock unconscious, especially in a boxing match; knock out.

Origin of KO

First recorded in 1920–25; initial letters of knock out
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for kayo

Historical Examples

  • Kayo Tortoni” is acknowledged the most famous woman character in sports cartoons.

    What's in the New York Evening Journal

    New York Evening Journal

British Dictionary definitions for kayo



noun plural kayos
  1. boxing another term for knockout
verb kayoes, kayos, kayoing or kayoed
  1. boxing another term for knock outSee knockout (verb)

Word Origin

C20: from the initial letters of knock out



verb KO's, KO'ing, KO'd, k.o.'s, k.o.'ing or k.o.'d
  1. a slang term for knock outSee knockout
noun plural KO's or k.o.'s
  1. a slang term for knockout
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for kayo

spelled-out form of K.O. (knockout), from 1923. Also used in 1920s as a slang reversal of OK.

Online Etymology Dictionary, © 2010 Douglas Harper