 Until late in the 20th century the word "radical" was used in chemistry to indicate any connected group of atoms, such as a methyl group or a carboxyl, whether it was part of a larger molecule or a molecule on its own.The qualifier "free" was then needed to specify the unbound case.Following recent nomenclature revisions, a part of a larger molecule is now called a functional group or substituent, and "radical" now implies "free".