Lath"er (lă&thlig;"&etilde;r), n. [AS. leáðor niter, in leáðorwyrt soapwort; cf. Icel. lauðr; perh. akin to E. lye.] 1. Foam or froth made by soap moistened with water.

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

Lath"er, v. t. [imp. & p. p. Lathered (?); p. pr. & vb. n. Lathering.] [AS. lēðrian to lather, anoint. See Lather, n. ] To spread over with lather; as, to lather the face.

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

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

• the foam made by rapidly stirring soap and water
  
• to cover with lather