The Collaborative International Dictionary
kakodyl
Cacodyl \Cac"o*dyl\, n. [Gr. ??????? ill-smelling (kako`s bad + ????? to smell) + -yl.] (Chem.) Alkarsin; a colorless, poisonous, arsenical liquid, As2(CH3)4, spontaneously inflammable and possessing an intensely disagreeable odor. It is the type of a series of compounds analogous to the nitrogen compounds called hydrazines. [Written also cacodyle, and kakodyl.]
Wiktionary
kakodyl
n. (archaic form of cacodyl English)