Definition of "K"

K¹

/keɪ/

letter
upper case, lower case k, plural Ks or K's
1. The eleventh letter of the English alphabet, called kay and written in the Latin script.
  Quotations
  The symbol K, however, was not entirely lost; it is found irregularly in inscriptions of all dates down to the times of the empire, and regularly as an initial abbreviation of Kalendæ, Karthago, Kæso (the proper name).
  1876, "C" in the Encyclopædia Britannica, 9th ed., Vol. IV, p. 616
number
upper case, lower case k
1. The ordinal number eleventh, derived from this letter of the English alphabet, called kay and written in the Latin script.

K²

noun
plural Ks
1. (law, informal) Abbreviation of contract.
2. (education, US) Abbreviation of kindergarten.
3. (often computing) Abbreviation of kilo-, 1,024.
4. (computing) A single character message used as an acknowledgement (ACK), meaning "previous message received and understood."
5. (Morse code) Abbreviation of go ahead, over, an indication that a message is complete and a reply is awaited.
6. (baseball) Abbreviation of strikeout. On a baseball scorecard, a frontwards K signifies striking out while swinging the bat, while a backwards K signifies striking out while looking.
7. (card games, chess) Abbreviation of king.
8. (biology) Abbreviation of carrying capacity.
9. (geology) Abbreviation of Cretaceous.
10. (knitting) Abbreviation of knit.
  Quotations
  Knit 3, p 1, k 2, purl 1, k 2, m 1, k 2 together, k 1.
  1855, Godey's Magazine, volume 51, page 71
11. (slang) Abbreviation of ketamine (a drug).
  Quotations
  At high levels of concentration of K in the blood, the observer/operator is cut off from his interlock with e.r., including the human consensus reality.
  1978, John C. Lilly, “Seduction by K”, in The Scientist, Philadelphia: Lippincott, page 167
12. (music) Abbreviation of Köchel number.
13. (UK, government) Abbreviation of Knighthood.
14. (economics) Abbreviation of capital.
15. (printing) Abbreviation of black.
16. (slang, from Jamaican Creole) Abbreviation of Kalashnikov.
  Quotations
  We used to run from the KKK but now we running from our brothers that be holding them K's.
  2011 August 16, “My People”‎performed by Kendrick Lamar,Jay Rock
  Yeti in the Serengeti, believe the myth. K-man stupid, rub together sticks.
  2018 October 16, “Demon Boy”, performed by Slowthai
  Keep the chopper, I'ma spray that. This is an AR, don't keep the K, man.
  2019 November 22, “Payback” (track 11), in Netflix&Deal‎, performed by 03 Greedo, Kenny Beats, OhGeesy, and Judge
  You come to my trap, bitch, you better knock. I keep a 'K and these bullets gon' flock.
  2021 November 19, “Pink 3 Remix”‎performed by PCAJAY
  A fuck nigga diss GG, he get hit with a K. I'll be back in the morning, just went to the A.
  2022 June 4, “OVO”‎performed by Big Yavo
  Bitch ass nigga get rocked. I walk in da trap with a Glock and a K in my sock. U fag ass nigga get popped. U a gay lil dumb ahh nigga came from TikTok. I'mma talk my shi won't stop. Bitch u all on my dick for a drop, nigga get off my cock.
  2022 September 25, “Dork”‎performed by Aeterluv
17. Abbreviation of kritik.

K³

interjection
1. (colloquial, text messaging, Internet slang) OK
  Quotations
  K, dad, I'll go to my room.
  2019, Justin Blackburn, The Bisexual Christian Suburban Failure Enlightening Bipolar Blues, page 23