The Collaborative International Dictionary of English v.0.48:

Cobalt \Co"balt\ (k[=o]"b[o^]lt; 277, 74), n. [G. kobalt, prob.
   fr. kobold, kobel, goblin, MHG. kobolt; perh. akin to G.
   koben pigsty, hut, AS. cofa room, cofgodas household gods,
   Icel. kofi hut. If so, the ending -old stands for older
   -walt, -wald, being the same as -ald in E. herald and the
   word would mean ruler or governor in a house, house spirit,
   the metal being so called by miners, because it was poisonous
   and troublesome. Cf. Kobold, Cove, Goblin.]
   1. (Chem.) A tough, lustrous, reddish white metal of the iron
      group, not easily fusible, and somewhat magnetic. Atomic
      weight 59.1. Symbol Co.
      [1913 Webster]

   Note: It occurs in nature in combination with arsenic,
         sulphur, and oxygen, and is obtained from its ores,
         smaltite, cobaltite, asbolite, etc. Its oxide colors
         glass or any flux, as borax, a fine blue, and is used
         in the manufacture of smalt. It is frequently
         associated with nickel, and both are characteristic
         ingredients of meteoric iron.
         [1913 Webster]

   2. A commercial name of a crude arsenic used as fly poison.
      [1913 Webster]

   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.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cobalt
    n 1: a hard ferromagnetic silver-white bivalent or trivalent
         metallic element; a trace element in plant and animal
         nutrition [syn: cobalt, Co, atomic number 27]

The Elements (07Nov00):

cobalt
Symbol: Co
Atomic number: 27
Atomic weight: 58.993
Light grey transition element. Some meteorites contain small amounts of
metallic cobalt. Generally alloyed for use. Mammals require small
amounts
of cobalt salts. Cobalt-60, an artificially produced radioactive isotope
of Cobalt is an important radioactive tracer and cancer-treatment agent.
Discovered by G. Brandt in 1737.


U.S. Gazetteer Places (2000):

Cobalt, MO -- U.S. village in Missouri
   Population (2000):    189
   Housing Units (2000): 89
   Land area (2000):     0.145300 sq. miles (0.376326 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.145300 sq. miles (0.376326 sq. km)
   FIPS code:            15220
   Located within:       Missouri (MO), FIPS 29
   Location:             37.545564 N, 90.288726 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Cobalt, MO
    Cobalt