mitten: [14] Etymologically, a mitten is ‘half a glove’. The word comes via Old French mitaine from Vulgar Latin *medietāna ‘cut off in the middle’ (originally an adjective, and applied to gloves, but subsequently used independently as a noun meaning ‘cut-off glove’). This in turn came from Latin medietās ‘half’ (source of English moiety [15]), a derivative of medius ‘middle’ (source of English medium). The abbreviated mitt dates from the 18th century. => medium, moiety[mitten etymology, mitten origin, 英语词源]