sole [ME] There are three different words ‘sole’, all Middle English. The two nouns are connected: the word for the under part of the foot comes via French from Latin solea ‘sandal, sill’, from solum ‘ground, sole’. The word was re-borrowed for the flat-fish, because its shape is reminiscent of a sole. The adjective for ‘only’ comes from Latin solus ‘alone’, source of solitary [ME], desolate [LME], and the musical solo [L17th]. Solitaire [E18th], both the single stone in its setting and the card game played by yourself, comes from the same source.