diol

This term is a specialized chemical designation used primarily in organic chemistry and biochemistry. It describes a specific structural class of alcohols, distinguishing them from monols (one hydroxyl group) or polyols (three or more hydroxyl groups).

In a laboratory or industrial context, the term is used to categorize substances based on their reactivity and physical properties, such as the hygroscopic nature of ethylene glycol. It is almost exclusively used in technical, scientific, or academic registers and is not encountered in general conversation.