russet: [13] Latin russus ‘red’ went back ultimately to the prehistoric Indo-European *reudh- ‘red’, which also produced English red. From it was descended Old French rous, whose modern form roux has given English roux ‘flour and butter mixture’ [19] (it is short for beurre roux ‘browned butter’). This formed the basis of a diminutive form rousset, which passed into English via Anglo-Norman russet. The application of the word to a red-skinned variety of apple dates from the 18th century. => red, roux[russet etymology, russet origin, 英语词源]