hat: [OE] Hat and hood are ultimately the same word, and denote literally ‘head-covering’. Both go back to Indo-European *kadh- ‘cover, protect’, which in the case of hat produced a Germanic derivative *khadnús, later *khattus. This was the source of English hat, and also of Swedish hatt and Danish hat (German hutt and Dutch hoed ‘hat’ are more closely related to English hood). => hood[hat etymology, hat origin, 英语词源]