Source : Webster's Revised Unabridged Dictionary (1913)

Chlorine \Chlo"rine\, n. [Gr. ? pale green, greenish yellow. So
   named from its color. See {Yellow}.] (Chem.)
   One of the elementary substances, commonly isolated as a
   greenish yellow gas, two and one half times as heavy as air,
   of an intensely disagreeable suffocating odor, and
   exceedingly poisonous. It is abundant in nature, the most
   important compound being common salt. It is powerful
   oxidizing, bleaching, and disinfecting agent. Symbol Cl.
   Atomic weight, 35.4.

   {Chlorine family}, the elements fluorine, chlorine, bromine,
      and iodine, called the {halogens}, and classed together
      from their common peculiarities.

Source : WordNet®

chlorine
     n : a common nonmetallic element belonging to the halogens; best
         known as a heavy yellow irritating toxic gas; used to
         purify water and as a bleaching agent and disinfectant;
         occurs naturally only as a salt (as in sea water) [syn: {Cl},
          {atomic number 17}]