mousse (n.) Look up mousse at
1892, in cookery sense, from French mousse, from Old French mousse "froth, scum," from Late Latin mulsa "mead," from Latin mulsum "honey wine, mead," from neuter of mulsus "mixed with honey," related to mel "honey" (see Melissa). Meaning "preparation for hair" is from 1977. As a verb in this sense from 1984.