n. An aliphatic hydrocarbon of chemical formula C5H12; either of the three isomers n-pentane, methyl-butane (isopentane), and di-methyl-propane (neopentane); volatile liquids under normal conditions.
the GNU version of the Collaborative International Dictionary of English
n. Any one of the three metameric hydrocarbons, C5H12, of the methane or paraffin series. They are colorless, volatile liquids, two of which occur in petroleum. So called because of the five carbon atoms in the molecule.
The Century Dictionary and Cyclopedia
n. Amyl hydrid, C5H12, a paraffin hydrocarbon existing in three modifications.
Word Usage
"They then adopt a more rational approach for the rest, with pentane, hexane, heptane, octane and onwards in Greek."