“+ noun
Etymology: International Scientific Vocabulary poly- + methylene
1. : a hydrocarbon constituted of methylene groups: as
a. : cycloparaffin
b. : a polymer of high molecular weight that resembles polyethylene except for its entirely linear and unbranched structure and that is usually made from diazomethane by loss of nitrogen
2. : a bivalent radical −(CH 2 ) n − consisting of a series of methylene groups
polymethylene halides