出典:Wiktionary
Middle English Yore, Jor, from 古期英語 Earp, corrupted from Ear + ƿ (abbreviation for ƿæter (“water”)); first element from Brythonic Isurā with loss of intervocalic s, ultimately from Proto-Indo-European *isərós (“vigorous, quick”), from *eis(ə, related to Sanskrit इषिरम् (iṣiram, “fast, quick”). Compare the Gaulish river Isara.