Aryl

In the context of organic molecules, aryl refers to any functional group or substituent derived from a simple aromatic ring, be it phenyl, thienyl, indolyl, etc. (see IUPAC nomenclature). "Aryl" is used for the sake of abbreviation or generalization.

A simple aryl group is phenyl, C6H5; it is derived from benzene. The tolyl group, CH3C6H4, is derived from toluene (methylbenzene). The xylyl group, (CH3)2C6H3, is derived from xylene (dimethylbenzene).

Biaryls may display axial chirality. Arylation is simply any chemical process in which an aryl group is attached to a substrate.