1a sweet or savory dish made as a smooth light mass with whipped cream and beaten egg white, flavored with chocolate, fish, etc., and typically served chilled:roulade of sole with a lobster moussedark chocolate mousse
2 [in singular] a mass of tiny bubbles that forms on the top of a glass of champagne or sparkling wine:the Brut Réserve possesses a wonderful creamy mousse of small, compact bubbles
3a light, foamy preparation used for styling hair:apply a dollop of volumizing mousse to the roots and work it in towards the ends of your hairexperiment with different styling products such as mousses and gels
a cosmetic or other skincare product with a foamy consistency:fragrant shower mousse
(also chocolate mousse) a brown frothy emulsion of oil and seawater formed by weathering of an oil slick.