Compositional etymology parsing the word as a compound of εὖ and ἔχω "to hold", but the latter is not explicit and is replaced by the synonym τηρέω, which makes the meaning clearer (elliptic etymology). The initial [l] is probably considered an added letter. From the semantic point of view, the etymology relies on the association of white with light and purity, themselves seen as "good" (εὖ): what is white is pure, therefore good.