-yl \_ə̇l, ˌil, -ˌēl, (when t, d, or n precedes) _əl; chiefly Brit ˌīl\noun combining form (-s) Etymology: Greek hylē wood, matter; first used in German benzoyl, literally, fundamental material of benzoic acid, from benz- + Greek hylē — more at hyle : chemical radical: as a.: univalent radical < ethyl > < pyridyl > < hydroxyl > b.: radical containing oxygen < carbonyl > < chromyl > including a few radicals of organic acids < acetyl > < glycyl > < succinyl > — compare -oyl