noun [C,U]
1 a cold DESSERT (= a sweet dish) made with cream and egg whites and flavoured with fruit, chocolate, etc.; a similar dish flavoured with fish, vegetables, etc:
a chocolate / strawberry mousse * salmon / mushroom mousse
2 a substance that is sold in AEROSOLS, for example the light white substance that is used on hair to give it a particular style or to improve its condition
