yugo.

From Old Spanish yugo, from Latin iugum, from Proto-Italic *jugom, from Proto-Indo-European *yugóm, a root shared by iungō (“to join”). As it does not display the usual expected sound shifts from Latin, Meyer-Lübke considered it a semi-learned medieval borrowing, while Coromines and Pascual see it as deriving from a dialectal variant akin to Leonese (and perhaps influenced by the semantically related word uncir). An Old Spanish form jogo, which did undergo the normal phonetic transitions, is attested. Compare the dialectal variants ubio, (l)uvio, chuvo, chugo, juvo, cf. also Aragonese chubo, Asturian xugu, Galician xugo, Portuguese jugo. The -v- in some of these forms may represent a Vulgar Latin pronunciation *jŭu(m); compare Old French jou, jof, Friulian jôf, Engadine Romansh giuf, Venetan dóvo, Logudorese Sardinian giuu, yuu. Doublet of yoga.