Seems to be the Swadesh term in Middle Breton.
The Catholicon (1499) translates French 'nuée', Latin 'nebula, nubes'.
Modern Breton koabr(enn) is rather a black cloud, cf. Favereau Dict. 418.
The Modern Breton terms koumoul (from Latin cumulus) and koguss (from Old French cocusse, a kind of hood, from Vulgar Latin coqucia) are attested only from Early Modern Breton onwards (Deshayes 2003, 406).|