1. A dessert or sweet food made of gelatine, whipped cream and a flavouring, such as chocolate, and chilled until stiffened: The caramel mousse at the end of the meal was spectacular.
2. A foamy substance applied to a person's hair to help style and to keep it tidy: The beautician applied mousse to Heather's new cut so that she would continue to look well-groomed.
3. Etymology: from French, foam; from Old French, "moss, foam", partly from Latin mulsa, "honey-sweet".

To apply an aerosol mixture to the hair to maintain a neat appearance: Sally moussed every day after she showered and shampooed her curls.

To apply an aerosol mixture to the hair to maintain a neat appearance: Sally moussed every day after she showered and shampooed her curls.