Source : Webster's Revised Unabridged Dictionary (1913)

Leather \Leath"er\, n. [OE. lether, AS. le?er; akin to D. leder,
   le[^e]r, G. leder, OHG. ledar, Icel. le?r, Sw. l["a]der, Dan.
   l[ae]der.]
   1. The skin of an animal, or some part of such skin, tanned,
      tawed, or otherwise dressed for use; also, dressed hides,
      collectively.

   2. The skin. [Ironical or Sportive]

   Note: Leather is much used adjectively in the sense of made
         of, relating to, or like, leather.

   {Leather board}, an imitation of sole leather, made of
      leather scraps, rags, paper, etc.

   {Leather carp} (Zo["o]l.), a variety of carp in which the
      scales are all, or nearly all, absent. See Illust. under
      {Carp}.

   {Leather jacket}. (Zo["o]l.)
      (a) A California carangoid fish ({Oligoplites saurus}).
      (b) A trigger fish ({Balistes Carolinensis}).

   {Leather flower} (Bot.), a climbing plant ({Clematis Viorna})
      of the Middle and Southern States having thick, leathery
      sepals of a purplish color.

   {Leather leaf} (Bot.), a low shrub ({Cassandra calyculata}),
      growing in Northern swamps, and having evergreen,
      coriaceous, scurfy leaves.

   {Leather plant} (Bot.), one or more New Zealand plants of the
      composite genus {Celmisia}, which have white or buff
      tomentose leaves.

   {Leather turtle}. (Zo["o]l.) See {Leatherback}.

   {Vegetable leather}.
      (a) An imitation of leather made of cotton waste.
      (b) Linen cloth coated with India rubber. --Ure.

Leather \Leath"er\, v. t. [imp. & p. p. {Leathered}; p. pr. &
   vb. n. {Leathering}.]
   To beat, as with a thong of leather. [Obs. or Colloq.] --G.
   Eliot.

Source : WordNet®

leather
     n : an animal skin made smooth and flexible by removing the hair
         and then tanning