He took a tremendous drink from his cup, the froth sticking to his moustache.
Their surfaces are a froth of magnetic storms, proportionally more violent than the worst weather on the Sun.
And judging from reviews, their froth is one element that is saving the show.
c.1300, from an unrecorded Old English word, or else from Old Norse froða "froth," from Proto-Germanic *freuth-. Old English had afreoðan "to froth," from the same root. The modern derived verb is from late 14c. Related: Frothed; frothing.