What is "tetramethylene"

Tetramethylene \Tet`ra*meth"yl*ene\, n. [Tetra- + methylene.] (Chem.)

1. A hypothetical hydrocarbon, C4H8, analogous to trimethylene, and regarded as the base of well-known series or derivatives.

2. Sometimes, an isomeric radical used to designate certain compounds which are really related to butylene.

n. 1 (context organic compound English) A hypothetical hydrocarbon, C₄H₈, analogous to trimethylene, and regarded as the base of well-known series or derivatives. 2 (context chemistry English) An isomeric radical used to designate certain compounds which are really related to butylene.