suds

Etymology

From the plural of sud, a variant of sod (“a bubbling or boiling”), equivalent to sud + -s. Related to seethe.

noun

1. (countable, uncountable) Lather; foam or froth formed by mixing soap and water.
   Mrs Durbeyfield, excited by her song, trod the rocker with all the spring that was left in her after a long day's seething in the suds. 1891, Thomas Hardy, Tess of the d'Urbervilles, volume 1, London: James R. Osgood, McIlvaine and Co., page 30
2. (slang) Beer.
   We went out for some pizza and suds.

verb

1. (transitive) To cover with, or as if with, soapsuds.
   We sudsed the car before washing it down until it gleamed like new.