Pen`ta*meth"yl*ene (?), n. [Penta- + methylene.] Chem.
A hypothetical hydrocarbon, C5H10, metameric with the amylenes, and the nucleus of a large number of derivatives; -- so named because regarded as composed of five methylene residues. Cf. Trimethylene, and Tetramethylene.
© Webster 1913.