significator

from The Collaborative International Dictionary of English v.0.48

Significator \Sig"ni*fi*ca`tor\, n. [Cf. F. significateur.]
   One who, or that which, signifies.
   [1913 Webster]

         In this diagram there was one significator which
         pressed remarkably upon our astrologer's attention.
                                                  --Sir W.
                                                  Scott.
   [1913 Webster]