Source : Webster's Revised Unabridged Dictionary (1913)

Permeable \Per"me*a*ble\, a. [L. permeabilis: cf. F.
   perm['e]able. See {Permeate}.]
   Capable of being permeated, or passed through; yielding
   passage; passable; penetrable; -- used especially of
   substances which allow the passage of fluids; as, wood is
   permeable to oil; glass is permeable to light. --I. Taylor.

Source : WordNet®

permeable
     adj : allowing (especially liquids) to pass or diffuse through;
           "permeable membranes"; "rock that is permeable by
           water" [ant: {impermeable}]