Source : Webster's Revised Unabridged Dictionary (1913)

Illustrative \Il*lus"tra*tive\, a.
   1. Tending or designed to illustrate, exemplify, or
      elucidate.

   2. Making illustrious. [Obs.]

Source : WordNet®

illustrative
     adj 1: clarifying by use of examples [syn: {exemplifying}]
     2: serving to demonstrate [syn: {demonstrative}]