"OK" (/oʊkeɪ/; also spelled "okay", "ok", or "O.K.") denotes approval, acceptance, agreement, assent, or acknowledgment. "OK", as an adjective, can also express acknowledgment without approval.[1] "OK" has frequently turned up as a loanword in many other languages.

As an adjective, "OK" means "adequate", "acceptable" ("this is OK to send out"), "mediocre" often in contrast to "good" ("the food was OK"); it also functions as an adverb in this sense. As an interjection, it can denote compliance ("OK, I will do that"), or agreement ("OK, that is fine"). As a verb and noun it means "assent" ("the boss OKed the purchase" and "the boss gave his OK to the purchase"). As a versatile discourse marker (or back-channeling item), it can also be used with appropriate voice tone to show doubt or to seek confirmation ("OK?" or "Is that OK?").[2]
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