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The name Vulchanov means most likely wolf or lupine, or more specifically "Descendant of the Wolf".
Behind the scenes
Considering that Professor Vulchanova founded Durmstrang, a school notoriously known not to accept Muggle-born students, it's possible that the Vulchanovs are an ancient pure-blood family. However, it is unknown whether this ban on Muggle-born students was enacted starting with Vulchanova, or during the two "dark periods" in Durmstrang history: the Headmastership of Harfang Munter or that of Igor Karkaroff, both after Vulchanova's time.
↑вълча or вълч translates from Bulgarian into English as Wolf or Lupine. The Easter European surname tradition indicates the suffix "ov" to convey, but not equal to, a belonging. In the case of Vulchanov it conveys, but not equal to, belonging to the wolf/lupine.