Soapy foam (6)
(Other definitions for lather that I've seen before include "Foam - tizzy (informal)" , "Frothy suds" , "Turner" , "Frothy bubbles from soap" , "Soapsuds" .)
(Other definitions for suds that I've seen before include "Lather" , "Lathery bubbles" , "Soap bubbles; scum" , "Foam from detergent" , "Froth made from soap" .)