The Columbia Encyclopedia, Sixth Edition. 2001-07.
hydroxyl group
(hdrk´sl) (KEY) , in chemistry, functional group that consists of an oxygen atom joined by a single bond to a hydrogen atom. An alcohol is formed when a hydroxyl group is joined by a single bond to an alkyl group or aryl group. A metal hydroxide is formed when a hydroxyl group is joined to a metal (e.g., sodium hydroxide).