The Collaborative International Dictionary of English v.0.48:

Surtout \Sur*tout"\, n. [F., fr. sur over + tout all.]
   A man's coat to be worn over his other garments; an overcoat,
   especially when long, and fitting closely like a body coat.
   --Gay.
   [1913 Webster]

WordNet (r) 3.0 (2006):

surtout
    n 1: a man's overcoat in the style of a frock coat