The Collaborative International Dictionary of English v.0.48:

Benzoyl \Ben"zoyl\, n. [Benzoic + Gr. ? wood. See -yl.]
   (Chem.)
   A compound radical, C6H5.CO-; the base of benzoic acid, of
   the oil of bitter almonds, and of an extensive series of
   compounds. [Formerly written also benzule.]
   [1913 Webster]