Coal
Etymology

The word originally took the form col in Old English, from reconstructed Proto-Germanic * kula (n), from Proto-Indo-European root * g (e) u-lo- "live coal". Germanic cognates include the Old Frisian kole, Middle Dutch cole, Dutch kool, Old High German chol, German Kohle and Old Norse kol. Irish gual is also a cognate via the Indo-European root.
change_case:english_lowercase