écume

écume is feminine in French.

foam

Related: écume de mer, écumer, écumeux

Inherited from Middle French écume, escume, from Old French escume (“froth, foam”), from Frankish *skūm (“froth, foam”), possibly via Vulgar Latin *scūma (compare Medieval Latin scuma), from Proto-Germanic *skūmaz (“foam”). Compare the rare Old French espume (“foam”), from Latin spūma (“foam, froth, slime”), which some sources hypothesise may have merged with or influenced the Germanic term, though there is no evidence to this effect.