Source : Webster's Revised Unabridged Dictionary (1913)

Skyrocket \Sky"rock`et\, n.
   A rocket that ascends high and burns as it flies; a species
   of fireworks.

Source : WordNet®

skyrocket
     n 1: propels bright light high in the sky, or used to propel a
          lifesaving line or harpoon [syn: {rocket}]
     2: sends a firework display high into the sky [syn: {rocket}]
     v : shoot up abruptly, like a rocket; "prices skyrocketed" [syn:
          {rocket}]