Mirko is of Serbian origin, derived from the Slavic element 'mir' which means 'peace'. It's a short form of names such as Mirandan, Mirislav, and Mirko itself can also be found in other Slavic languages like Croatian and Slovenian. The name has gained some popularity worldwide, but it remains relatively uncommon outside of its region of origin.
"Mirko experienced peak popularity in recent years, with a notable spike of 16 births in 2014 and consistently high numbers since 2015. However, it was more common in the late 19th to early 20th century, with fluctuations in usage until around the 1980s."