Diol is a term used to describe a molecule containing two hydroxyl groups (-OH) attached to different carbon atoms. A diol can also be referred to as a glycol or a dihydroxy compound. The word "glycol" comes from Greek "glykys," meaning sweet, as many diols have a sweet taste. Some synonyms for diol are dioxy compound, di-functional compound, di-hydroxy alcohol, and 1,2-diol. Examples of diols include ethylene glycol, propylene glycol, and butanediol, which are used in various industrial applications such as antifreeze, solvents, and plastics. Diols also play a significant role in organic chemistry, as they can act as important intermediates in the synthesis of more complex molecules.