O.K.

1. Oklahoma

2. Ладно, хорошо, добро

Meaning:

Satisfactory — all correct.

Origin:

Possibly the most researched phrase of them all, but with no clear evidence as to the origin. The contenders are:

A shortened version of 'Oll Korrect'. Used by President Andrew Jackson.

'Old Kinderhook' — nickname of President Martin van Buren.

'Aux quais' — the mark put on bales of cotton in Mississippi river ports.

'0 killed' — the report of the night's death toll during the First World War.

'Orl Korrect' — military reporting indicating troops were in good order.

etc, etc.