Cacodyl \Cac"o*dyl\, n. [Gr. ??????? ill-smelling (????? 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.]

Source: Webster's Revised Unabridged Dictionary (1913)