This is the 10939th most frequent German word.
schaum
Foam.
Here, 'Schaum' is metaphorically used to signify something unsubstantial or insignificant.
Sein Vorschlag ist nichts als heiße Luft, reiner Schaum.
His proposal is nothing but hot air, pure froth.
Here, 'Schaum' means 'foam', referring to the frothy appearance on the surface of the coffee.
Der Schaum auf meinem Kaffee sieht schön aus.
The foam on my coffee looks beautiful.
In this sentence, 'Badeschaum' (bath foam) describes the sudsy substance used while bathing, derived from 'Schaum'.