What does "cobalt" mean?

Cobalt: A commercial name of a crude arsenic used as fly poison. Cobalt bloom. Same as Erythrite. -- Cobalt blue, a dark blue pigment consisting of some salt of cobalt, as the phosphate, ignited with alumina; -- called also cobalt ultramarine, and Thenard's blue. -- Cobalt crust, earthy arseniate of cobalt. -- Cobalt glance. (Min.) See Cobaltite. -- Cobalt green, a pigment consisting essentially of the oxides of cobalt and zinc; -- called also Rinman's green. -- Cobalt yellow (Chem.), a yellow crystalline powder, regarded as a double nitrite of cobalt and potassium.