The Collaborative International Dictionary of English v.0.48:

Parabolically \Par`a*bol"ic*al*ly\
   (p[a^]r`[.a]*b[o^]l"[i^]*kal*l[y^]), adv.
   1. By way of parable; in a parabolic manner.
      [1913 Webster]

   2. In the form of a parabola.
      [1913 Webster]