The Collaborative International Dictionary of English v.0.48:

hierarchic \hi`er*arch"ic\, hierarchical \hi`er*arch"ic*al\, a.
   [Cf. F. hi['e]rarchique.]
   Of or pertaining to a hierarchy; ordered in a hierarchy. --
   Hi`er*arch`ic*al*ly, adv.

   Syn: hierarchical, hierarchal.
        [1913 Webster]

   2. Pertaining to a transitive relation between objects by
      which they may be ordered into a hierarchy; as, a
      hierarchical relation.
      [PJC]

WordNet (r) 3.0 (2006):

hierarchically
    adv 1: in a hierarchical manner; "hierarchically organized"