Webster's Revised Unabridged Dictionary · 1913

Lather

Lather (lat"ẽr) , noun

[Anglo-Saxon leáeor niter, in leáeorwyrt soapwort; compare Icelandic lauer; perh. akin to English lye.]

1.
Foam or froth made by soap moistened with water.
2.
Foam from profuse sweating, as of a horse.

Lather (lat"ẽrd) , transitive verb

[Anglo-Saxon lēerian to lather, anoint. See Lather, n. ]

To spread over with lather; as, to lather the face.

Lather , intransitive verb

To form lather, or a froth like lather; to accumulate foam from profuse sweating, as a horse.

Lather , transitive verb

[Compare Leather.]

To beat severely with a thong, strap, or the like; to flog. [Low]