What is "phenylene"

Phenylene \Phe"nyl*ene\, n. (Chem.) A hypothetic radical ( C6H4) occurring in certain derivatives of benzene; as, phenylene diamine.

n. (context chemistry English) Any of three isomeric divalent aromatic radicals derived from benzene by removing two hydrogen atoms from the ortho-, meta- or para- positions.

The phenylene group (CH) is based on a di-substituted benzene ring ( arylene). For example, poly(p-phenylene) is a polymer built up from para-phenylene repeating units.