- a colorless, flammable gas, C4H10, a saturated aliphatic existing in two isomeric forms: used chiefly in the manufacture of rubber and as fuel.
- a colourless flammable gaseous alkane that exists in two isomeric forms, both of which occur in natural gas. The stable isomer, n -butane, is used mainly in the manufacture of rubber and fuels (such as Calor Gas). Formula: C 4 H 10
