The Greek phrase 'Ola Kala' means 'All correct' in English. As per a popular theory, the term 'OK' started 185 years ago in office of American journalist Charles Gordon Greene. At that time, to make articles more interesting, deliberate misspellings were used. In this process, instead of 'All correct,' 'Oll Korrect' began to be written. Its short form became 'OK.'