How can we differentiate between glycols and glycerol?

Ethylene glycol is the most popular glycol in chemical industry. All alcohols having two or more of -OH groups are called glycol. - Glucose, fructose and Sugars contain larger numbers of -OH groups but they are not termed as Glycols. Glycerol is a specific alcohol containing 3 -OH groups. It is 1,2,3 trihydroxy propane. It is also termed as propane 123 glycol, and also as Glycerin / Glycerine. The glycerol substructure is a central component of most vegetable oils, fats and other lipids like phospho lipids.