a sweet but poisonous syrupy liquid used as an antifreeze and solvent
"The mechanic spilled some glycol on the garage floor, creating a sticky, sweet-smelling puddle that looked harmless until he realized it was toxic antifreeze."
any of a class of alcohols having 2 hydroxyl groups in each molecule
"Chemists classify ethylene glycol as a simple diol because its structure contains exactly two hydroxyl groups attached to adjacent carbon atoms."
Any aliphatic diol.
"Chemists classify ethylene glycol and propylene glycol as common examples of any aliphatic diol used in antifreeze formulations."