What is "yatsko"

Yatsko (in international transcription:[jɑːc'ko]; in English transcription: [jɑːts'ko]; Russian spelling: Яцко) is a Slavic surname that can be found in Russia, Belarus, Ukraine, the United States, Moldova and some other countries. In English speaking countries it is pronounced with the first syllable stressed [ˈjɑːtskoʊ] and has other less common variants of spelling: 'Iatsko', 'Jaczko'. The surname is rather rare and hasn't been listed among the most common surnames in the above mentioned countries.