What is "slavonic-serbian"

Slavonic-Serbian, Slavo-Serbian, or Slaveno-Serbian (славяносербскій, славено-сербскiй, slaveno-serbski or словенскій, slovenski; ) was a literary language used by the Serbs in the Habsburg Empire, mostly in what is now Vojvodina, from the mid-18th century to the first decades of the 19th century. It was a linguistic blend of Church Slavonic of the Russian recension, vernacular Serbian ( Štokavian dialect), and Russian.