Source : Webster's Revised Unabridged Dictionary (1913)

Firework \Fire"work`\, n.
   1. A device for producing a striking display of light, or a
      figure or figures in plain or colored fire, by the
      combustion of materials that burn in some peculiar manner,
      as gunpowder, sulphur, metallic filings, and various
      salts. The most common feature of fireworks is a paper or
      pasteboard tube filled with the combustible material. A
      number of these tubes or cases are often combined so as to
      make, when kindled, a great variety of figures in fire,
      often variously colored. The skyrocket is a common form of
      firework. The name is also given to various combustible
      preparations used in war.

   2. pl. A pyrotechnic exhibition. [Obs. in the sing.]

            Night before last, the Duke of Richmond gave a
            firework.                             --Walpole.

Source : WordNet®

firework
     n : (usually plural) a device with an explosive that burns at a
         low rate and with colored flames; can be used to
         illuminate areas or send signals etc. [syn: {pyrotechnic}]