The Collaborative International Dictionary of English v.0.48:

Glyceryl \Glyc"er*yl\, n. [Glycerin + -yl.] (Chem.)
   A compound radical, C3H5, regarded as the essential radical
   of glycerin. It is metameric with allyl. Called also
   propenyl.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Propenyl \Pro"pe*nyl\, n. [Propene + -yl.] (Chem.)
   A hypothetical hydrocarbon radical, C3H5, isomeric with
   allyl and glyceryl, and regarded as the essential residue of
   glycerin. Cf. Allyl, and Glyceryl.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Allyl \Al"lyl\, n. [L. allium garlic + -yl.] (Chem.)
   An organic radical, C3H5, existing especially in oils of
   garlic and mustard.
   [1913 Webster]