The Collaborative International Dictionary of English v.0.48:

Archetypal \Ar"che*ty`pal\, a.
   Of or pertaining to an archetype; consisting a model (real or
   ideal) or pattern; original. "One archetypal mind."
   --Gudworth.
   [1913 Webster]

   Note: Among Platonists, the archetypal world is the world as
         it existed as an idea of God before the creation.
         [1913 Webster]

WordNet (r) 3.0 (2006):

archetypal
    adj 1: representing or constituting an original type after which
           other similar things are patterned; "archetypal
           patterns"; "she was the prototypal student activist"
           [syn: archetypal, archetypical, prototypal,
           prototypic, prototypical]