1, The full form of OK is Oll Korrect. It’s used on Academic & Science ,Language & Linguistics in Worldwide

OK (okay) is a colloquial English word denoting approval, acceptance, assent, or acknowledgment.

OK is most likely short for “Oll Korrect” or “Ole Kurreck” or “Orl Korrekt”, a jokey misspelling of “All Correct” that needs a little historical context to make sense. In the late 1830s, a slang fad inspired young, educated folks in New York and make tongue-in-cheek acronyms for deliberate misspellings of common phrases. This led to arcane abbreviations like KY for “no use” (know yuse) and NC for “enough said” (nuff ced).

Note:

According to American etymologist and lexicographer Allen Walker Read, OK did not stem from the Choctaw word okeh or oke. Nor did it come from olla kalla, Greek for “all good.”

2, The full form of OK is Oklahoma. It’s used on Regional ,States & Districts in United States

Oklahoma (OK) is a state located in the South Central region of the United States of America.

3, The full form of OK is Old Kinderhook. It’s used on Society & Culture ,Celebrities & Famous in United States

Old Kinderhook (OK) was a nickname for Martin Van Buren, the eighth President of the United States from 1837 to 1841. During re-election campaign, he was called Old Kinderhook (OK), as he was from Kinderhook, New York, United States. “O.K. Clubs” were created to support Van Buren’s political campaigns.

4, The full form of OK is Czech Airlines. It’s used on Transport & Travel ,Airline Codes in Czech Republic

Czech Airlines (IATA code:OK, ICAO: CSA) is the national airline of the Czech Republic.