lather
n. C / Un. a thick, soapy foam that you get when you rub soap or shampoo into your skin or hair.
n. a thick, frothy mass of soap and water produced by agitation. Often used in the context of personal hygiene or industrial cleaning.
He rubbed the soap until his hands were full of lather.
The mechanic used a high-pressure sprayer to create a thick lather before washing the car.
The chef found that the eggs whipped much more easily once the lather from the previous dishwashing had been rinsed away from the stainless steel bowl.
From Middle English lather, from Old English lēaþor (“a kind of nitre used for soap, soda”), from Proto-West Germanic lauþr, from Proto-Germanic lauþrą (“that which is used for washing, soap”), from Proto-Indo-European lówh₃trom (“that which is used for washing”), from lewh₃-, *lowh₃- (“to wash, bathe”). Cognate with Swedish lödder (“lather, foam, froth, soap”), Icelandic löður (“foam, froth, a kind of niter used for soap”), Old Irish loathar (“wash-basin”), Ancient Greek λουτρόν (loutrón, “a bath, wash-room”), Latin lavō (“I wash”), Albanian laj (“I wash”), Ancient Greek λούω (loúō). More at lye.
From Middle English lethren, from Old English lēþrian, lȳþrian, līeþrian (“to anoint, smear, lather”), from Old English lēaþor (“a kind of niter used for soap, soda”). See above.