About the Rousseau surname
The surname Rousseau is associated with an older descriptive nickname. Rousseau is a diminutive of the French word for “red-haired” and may have described someone with reddish hair or complexion. The surname therefore fits within the tradition of descriptive nicknames that later became hereditary. The same nickname could be given independently to different people, producing unrelated family lines.
Pronunciation:
Rou-so/ʁuso/