Curtis or Curtiss is a common English given name and surname of Anglo-Norman origin, deriving from the Old French curteis (Modern French courtois) which was in turn derived from Latin cohors. Nicknames include Curt, Curty and Curtie. The name means "polite, courteous, or well-bred". It is a compound of curt- "court" and -eis "-ish". The spelling u to render [u] in Old French was mainly Anglo-Norman and Norman, when the spelling o [u] was the usual Parisian French one, Modern French ou [u].
https://en.wikipedia.org/wiki/Curtis