caoir

a blaze, stream of sparks, a coal, Irish caor, Early Irish cáer, *kairo, English hoar (*kairo-), Teutonic root hai in Norse heið, atmospheric clearness, Old High German hei, heat, English heat; Sanskrit kêtus, light. More near are Greek $$Gkíris (lamp, Hes.), Sanskrit kirán$$.a, a ray, clear, has been also suggested. caoran, a peat ember.