Source : Webster's Revised Unabridged Dictionary (1913)

Orbiculate \Or*bic"u*late\, Orbiculated \Or*bic"u*la`ted\, a.
   [L. orbiculatus. See {Orbicular}.]
   Made, or being, in the form of an orb; having a circular, or
   nearly circular, or a spheroidal, outline.

   {Orbiculate leaf} (Bot.), a leaf whose outline is nearly
      circular.

Source : WordNet®

orbiculate leaf
     n : circular or nearly circular