Source : Webster's Revised Unabridged Dictionary (1913)

Lather \Lath"er\, n. [AS. le['a][eth]or niter, in
   le['a][eth]orwyrt soapwort; cf. Icel. lau?r; perh. akin to E.
   lye.]
   1. Foam or froth made by soap moistened with water.

   2. Foam from profuse sweating, as of a horse.

Lather \Lath"er\, v. t. [imp. & p. p. {Lathered}; p. pr. & vb.
   n. {Lathering}.] [AS. l[=e][eth]rian to lather, anoint. See
   {Lather}, n. ]
   To spread over with lather; as, to lather the face.

Lather \Lath"er\, v. i.
   To form lather, or a froth like lather; to accumulate foam
   from profuse sweating, as a horse.

Lather \Lath"er\, v. t. [Cf. {Leather}.]
   To beat severely with a thong, strap, or the like; to flog.
   [Low]

Source : WordNet®

lather
     n 1: the froth produced by soaps or detergents [syn: {soapsuds},
          {suds}]
     2: agitation resulting from active worry; "don't get in a
        stew"; "he's in a sweat about exams" [syn: {fret}, {stew},
         {sweat}, {swither}]
     3: a workman who puts up laths
     4: the foam resulting from excessive sweating (as on a horse)
     v 1: cover with soap; "lather your body when you shower"
     2: beat severely with a whip or rod; "The teacher often flogged
        the students"; "The children were severely trounced" [syn:
         {flog}, {welt}, {whip}, {lash}, {slash}, {strap}, {trounce}]
     3: form a lather; "The shaving cream lathered"
     4: rub soap all over, usually with the purpose of cleaning
        [syn: {soap}]