From The Collaborative International Dictionary of English v.0.48:
Cadmium \Cad"mi*um\, n. [NL. See Cadmia.] (Chem.)
A comparatively rare element related to zinc, and occurring
in some zinc ores. It is a white metal, both ductile and
malleable. Symbol Cd. Atomic weight 111.8. It was discovered
by Stromeyer in 1817, who named it from its association with
zinc or zinc ore.
[1913 Webster]
Cadmium yellow, a compound of cadmium and sulphur, of an
intense yellow color, used as a pigment.
[1913 Webster]