suds

Concise Oxford English Dictionary © 2008 Oxford University Press:
suds/sʌdz/

▶plural noun

• 1 froth made from soap and water.

• 2 N. Amer. informal beer.

▶verb chiefly N. Amer. cover or wash in soapy water.

■ form suds.

– derivatives
sudsy adjective .

– origin C19: perh. orig. denoting the flood water of the fens; cf. Mid. Low Ger. sudde, MDu. sudse ‘marsh, bog’; prob. rel. to seethe.