Noah Webster
Lather
LATH'ER, verb intransitive
To form a foam with water and soap; to become froth, or frothy matter.
LATH'ER, verb transitive To spread over with the foam of soap.
LATH'ER, noun
1. Foam or froth made by soap moistened with water.
2. Foam or froth from profuse sweat, as of a horse.