Source : Webster's Revised Unabridged Dictionary (1913)

Strontium \Stron"ti*um\, n. [NL. See {Strontia}.] (Chem.)
   A metallic element of the calcium group, always naturally
   occurring combined, as in the minerals strontianite,
   celestite, etc. It is isolated as a yellowish metal, somewhat
   malleable but harder than calcium. It is chiefly employed (as
   in the nitrate) to color pyrotechnic flames red. Symbol Sr.
   Atomic weight 87.3.

Source : WordNet®

strontium
     n : a soft silver-white or yellowish metallic element of the
         alkali metal group; turns yellow in air; occurs in
         celestite and strontianite [syn: {Sr}, {atomic number 38}]