On ‪#‎ThisDayInHistory‬ 1839, the initials “O.K.” are first published in The Boston Morning Post. Meant as an abbreviation for “oll korrect,” a popular slang of “all correct” at the time, OK steadily made its way into the everyday speech of Americans.

OK

adverb or adjective \ō-ˈkā, in assenting or agreeing also ˈō-ˌkā\

Popularity: Top 40% of words

Simple Definition of OK: fairly good : not very good or very bad : acceptable or agreeable: not ill, hurt, unhappy, etc.

Source: Merriam-Webster's Learner's Dictionary

OK is listed as a word at .merriam-webster.com/dictionary

More Info: www.history.com