sorrel

the word 'sorrel' for the plant and the color originates from the old french 'sorel', meaning 'reddish-brown'. this french term is itself derived from the frankish word 'saur', meaning 'dry' or 'withered', which influenced the old high german 'sōr', also meaning 'dry'. the semantic connection likely flows from the concept of dryness to a dull, brownish color, which was then applied to both the hue of a horse's coat and the characteristic sour, somewhat 'drying' taste of the plant's leaves. the two modern meanings, therefore, share a common ancestor in describing a particular quality—first a color, then by extension the plant associated with a similarly astringent taste.

this word is a simplex loanword from old french. it is not productively formed from separable morphemes in modern english.