DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Sizable \Siz"a*ble\, a.
      1. Of considerable size or bulk. "A sizable volume." --Bp.
         Hurd.
         [1913 Webster]
      2. Being of reasonable or suitable size; as, sizable timber;
         sizable bulk. --Arbuthnot.
         [1913 Webster]