Definition from Wiktionary, the free dictionary
IUPAC nomenclature, from but- (“four carbon prefix”) + -ane (“alkane suffix”), the former is derived from the same stem as the foul-smelling carboxylic acid liberated in rancid butter, "butyric acid", hence cognate with butter.
- (organic chemistry) A hydrocarbon (either of the two isomers of C4H10 n-butane, and 2-methyl-propane) found in gaseous petroleum fractions.
- (organic chemistry, uncountable) The n-butane isomer only.
Derived terms 
Related terms 
the organic compound