Ukraine: by 1670s, from Russian or Polish Ukraina, a specific use of ukraina "border, frontier," from Old Russian oukraina, from ou "by, at" + kraj region. The territory was so called because it was the borderland or 'frontier zone' of medieval Russia at the time of the Tatar invasion in the 13th century.
Ukraine was formerly also known as Little Russia, so called by contrast with Great Russia, when the medieval principality here became separated from 'mainstream' czarist Russia as a result of the Mongol invasion. [Room, 2006]
Ukraine: by 1670s, from Russian or Polish Ukraina, a specific use of ukraina "border, frontier," from Old Russian oukraina, from ou "by, at" + kraj region. The territory was so called because it was the borderland or 'frontier zone' of medieval Russia at the time of the Tatar invasion in the 13th century.
Ukraine was formerly also known as Little Russia, so called by contrast with Great Russia, when the medieval principality here became separated from 'mainstream' czarist Russia as a result of the Mongol invasion. [Room, 2006]
https://www.etymonline.com/search?q=ukraine
the emphasis is mine