The Collaborative International Dictionary
Malonyl
Malonyl \Mal"o*nyl\, n. [Malonic + -yl.] (Chem.) A divalent diacyl radical, CH2.(CO)2, from malonic acid.
Wiktionary
malonyl
n. (context organic chemistry especially in combination English) The divalent radical CH2(COO-)2 derived from malonic acid