Source : Webster's Revised Unabridged Dictionary (1913)

Cynosure \Cy"no*sure\ (s?"n?-sh?r or s?n"?-sh?r; 277), n. [L.
   Cynosura theconstellation Cynosure, Gr. ????? dog's tail, the
   constellation Cynosure; ????, ????, dog + ???? tail.
   See{Cynic}.]
   1. The constellation of the Lesser Bear, to which, as
      containing the polar star, the eyes of mariners and
      travelers were often directed.

   2. That which serves to direct. --Southey.

   3. Anything to which attention is strongly turned; a center
      of attraction.

            Where perhaps some beauty lies, The cynosure of
            neighboring eyes.                     --Milton.

Source : WordNet®

cynosure
     n 1: something that provides guidance (as Polaris guides
          mariners); "let faith be your cynosure to walk by"
     2: something that strongly attracts attention and admiration;
        "if he was the cynosure of all eyes he didn't notice"