'Butyl' definitions:

Definition of 'butyl'

From: WordNet
noun
A hydrocarbon radical (C4H9)

Definition of 'Butyl'

From: GCIDE
  • Butyl \Bu"tyl\, n. [L. butyrum butter + -yl. See Butter.] (Chem.) A compound radical, regarded as butane, less one atom of hydrogen. [1913 Webster]