Source : Webster's Revised Unabridged Dictionary (1913)

Bipinnate \Bi*pin"nate\, Bipinnated \Bi*pin"na*ted\, a. [Pref.
   bi- + pinnate; cf. F. bipinn['e]. Cf. {Bipennate}.]
   Twice pinnate.

Source : WordNet®

bipinnate
     adj : of a leaf shape; having doubly pinnate leaflets (as ferns)