"OK" is an English word that can denote approval, acceptance, agreement, assent, acknowledgment, or a sign of indifference. It is frequently used as a loanword in other languages. The word "OK" originated in American English and first appeared as an abbreviation for "Oll Korrect," printed in a satirical article about grammar in 1839. The words origins were only revealed in the 1960s when etymologist Allen Read did some digging. The abbreviation "OK" stood for "all correct," which was a jokey way of saying "all correct". The word "OK" can be used as an adjective, adverb, interjection, conjunction, or noun. As an adjective, it principally means "adequate" or "acceptable" as a contrast to "bad". It can also mean "mediocre" when used in contrast with "good". As an interjection, it can denote compliance or agreement. In summary, "OK" is a versatile word that can be used in many different contexts to denote approval, acceptance, agreement, or acknowledgment.