Rebais has historically been attested in Latin as
Rebascis in 635/636 and
Rebascum in 1214. The toponym
Rebais is of Germanic origin, deriving from a High German dialect, ultimately from Proto-West-Germanic
*hross. The Germanic hydronym
*-bak(i) entered the French language via High German, and took on two forms: the Germanic form
-bach and Romantic
-bais. ==Population==