Source : Webster's Revised Unabridged Dictionary (1913)

Dispersive \Dis*pers"ive\, a.
   Tending to disperse.

   {Dispersive power} (Opt.), the relative effect of a material
      in separating the different rays of light by refraction,
      as when the substance is formed into a prism. --
      {Dis*pers"ive*ness}, n.