>Initials of Omnis Korrecta ("all correct")

The fact that half of the rest of the entries are saying "oll korrect" makes me believe that this is the one. Especially with this example too.

>A contemporary news report of the 1866 transatlantic telegraph cable says "The following telegram has been received from Mr. R. A. Glass, Managing Director of the Telegraph Construction and Maintenance Company (Limited) :— 'O.K.,' (all correct)."