The Collaborative International Dictionary
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.
Wiktionary
n. A man's overcoat.
WordNet
n. a man's overcoat in the style of a frock coat
Wikipedia
A surtout coat is a man's frock coat, of the kind worn by cavalry officers over their uniforms in the 18th and early 19th centuries. It was occasionally worn by British soldiers during the Revolutionary War (American War of Independence).
Surtout is also a French word meaning "above all" or "especially".
Usage examples of "surtout".
Tout de suite Roger se mit a ecrire cette lettre, qui fut longuement explicative et surtout ardemment passionnee, mais qui ne dit pas un mot des projets de mariage avec Dayelle fils.
Arrives a la maison de jeu, Savine et Leplaquet monterent le perron, Roger, qui voulait faire parler Dayelle sur madame de Barizel et surtout sur Corysandre, parut peu dispose a les suivre.
What would become of a Greenland whale, say, in those shuddering, icy seas of the North, if unsupplied with his cosy surtout?
Thus I stared at balmacaans and surtouts, dolmans and jerkins of paduasoy, matelasse, and a hundred other costly fabrics without ever going into the places that displayed them, or even stopping to examine them.
What would become of a Greenland whale, say, in those shuddering, icy seas of the north, if unsupplied with his cosy surtout?
The visitor was about fifty-two years of age, dressed in one of the green surtouts, ornamented with black frogs, which have so long maintained their popularity all over Europe.
This man was dressed in a greatcoat, or rather a surtout, a little worse for the journey, but which exhibited the ribbon of the Legion of Honor still fresh and brilliant, a decoration which also ornamented the under coat.
Its snowy wastes were bare of tableware, save for a quartet of surtouts, the seasons personified.
For ornament, there were golden surtouts in the shape of fruiting and blossoming trees.
And there are the office lads in their first surtouts, who feel a befitting contempt for boys at day-schools, club as they go home at night, for saveloys and porter, and think there's nothing like 'life.