Please read Alexey Sklyarenko's annotations on Pale Fire, Ada and other Nabokov works here.
In his Commentary to Shade’s poem Kinbote (in VN’s novel Pale Fire, 1962, Shade’s mad commentator who imagines that he is Charles the Beloved, the last self-exiled king of Zembla) says that the Zemblan word coramen denotes the rude strap with which a Zemblan herdsman attaches his humble provisions and ragged blanket to the meekest of his cows when driving them up to the vebodar (upland pastures):
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