The Collaborative International Dictionary of English v.0.48:

Potassium \Po*tas"si*um\, n. [NL. See Potassa, Potash.]
   (Chem.)
   An Alkali element, occurring abundantly but always combined,
   as in the chloride, sulphate, carbonate, or silicate, in the
   minerals sylvite, kainite, orthoclase, muscovite, etc. Atomic
   weight 39.0. Symbol K (Kalium).
   [1913 Webster]

   Note: It is reduced from the carbonate as a soft white metal,
         lighter than water, which oxidizes with the greatest
         readiness, and, to be preserved, must be kept under
         liquid hydrocarbons, as naphtha or kerosene. Its
         compounds are very important, being used in glass
         making, soap making, in fertilizers, and in many drugs
         and chemicals.
         [1913 Webster]

   Potassium permanganate, the salt KMnO4, crystallizing in
      dark red prisms having a greenish surface color, and
      dissolving in water with a beautiful purple red color; --
      used as an oxidizer and disinfectant. The name chameleon
      mineral is applied to this salt and also to potassium
      manganate.

   Potassium bitartrate. See Cream of tartar, under Cream.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chameleon \Cha*me"le*on\ (k[.a]*m[=e]"l[-e]*[u^]n), n. [L.
   Chamaeleon, Gr. chamaile`wn, lit., "ground lion;" chamai` on
   the ground + le`wn lion. See Humble, and Lion.] (Zool.)
   1. A lizardlike reptile of the genus Cham[ae]leo, of
      several species, found in Africa, Asia, and Europe. The
      skin is covered with fine granulations; it has eyes which
      can move separately, the tail is prehensile, and the body
      is much compressed laterally, giving it a high back. It is
      remarkable for its ability to change the color of its skin
      to blend with its surroundings. [Also sometimes spelled
      chamaeleon.]
      [1913 Webster +PJC]

   Note: Its color changes more or less with the color of the
         objects about it, or with its temper when disturbed. In
         a cool, dark place it is nearly white, or grayish; on
         admitting the light, it changes to brown, bottle-green,
         or blood red, of various shades, and more or less
         mottled in arrangment. The American chameleons belong
         to Anolis and allied genera of the family
         Iguanid[ae]. They are more slender in form than the
         true chameleons, but have the same power of changing
         their colors.
         [1913 Webster]

   2. a person who changes opinions, ideas, or behavior to suit
      the prevailing social climate; an opportunist.
      [PJC]

   Chameleon mineral (Chem.), the compound called potassium
      permanganate, a dark violet, crystalline substance,
      KMnO4, which in formation passes through a peculiar
      succession of color from green to blue, purple, red, etc.
      See Potassium permanganate, under Potassium.
      [1913 Webster]