What's the difference between a souffle and a mousse?
There is no strict delineation between these two terms.  Either can be savory or sweet.

Some common differences are:


Mousses may get their foaminess from  from plain whipped egg whites, a meringue, whole eggs, whipped cream, or  something else; a souffle is always leavened by whipped egg whites.
Mousses (except for some seafood mousses, which are gently poached) are rarely cooked as a whole dish; souffles are always baked to get additional rise.
Mousses are almost always served cold; souffles are usually served hot, immediately out of the oven to retain the additional rise they get in the heat of the oven.


One might consider souffles a type of baked mousse, much as quiches are a specific type of tart, but that terminology is rarely used.

See also:

Ochef