(Chem.) A combining form, also used adjectively, indicating hydroxyl as an ingredient. [ 1913 Webster ]
Hydroxy acid (Chem.),
n. [ Hydro-, 2 + oxygen + -yl. ] (Chem.) A compound radical, or unsaturated group,
n. [ Hydroxyl + amine. ] (Chem.) A nitrogenous, organic base,
n. a methyl radical with a hydroxyl group replacing one of the hydrogen atoms. [ WordNet 1.5 ]
n. A crystalline amino acid (