The Collaborative International Dictionary of English v.0.48:

heuristically \heu*ris"ti*cal*ly\
   (h[-u]*r[i^]s"t[i^]*kal*l[y^]), n.
   In a heuristic manner; by using a heuristic method; by
   serving as a heuristic method; as, a heuristically guided
   search technique; a heuristically valuable theory.
   [PJC]