Heptane \Hep"tane\, n. [Gr. "epta` seven.] (Chem.)
Any one of several isometric hydrocarbons, {C7H16}, of the
paraffin series (nine are possible, four are known); -- so
called because the molecule has seven carbon atoms.
Specifically, a colorless liquid, found as a constituent of
petroleum, in the tar oil of cannel coal, etc.
[1913 Webster]