feather-edged

from The Collaborative International Dictionary of English v.0.48

Feather-edged \Feath"er-edged`\, a.
   Having a feather-edge; also, having one edge thinner than the
   other, as a board; -- in the United States, said only of
   stuff one edge of which is made as thin as practicable.
   [1913 Webster]