rime n.

"hoarfrost, white frost," Old English hrim, from Proto-Germanic *khrima- (source also of Old Norse hrim, Dutch rijm, German Reif). Old French rime is of Germanic origin. Rare in Middle English and usually there as rime-frost; after c. 1500 it seems to have survived mainly in Scottish and northern English until it was revived in literary use in late 18c. Related: Rimy.