Depending on the context and source, caraco and casaquin are different styles of jacket, or two types of the same garment in different styles, related like the robe à l'anglaise and robe à la française: Both had versions à la française and à l'anglaise, the difference being whether the pleats in back are loose or stiched to the lining.
Depending on the time of century, the jackets were thigh-length all around, or short in front with more or less gathered basques at the back.
casaquin à la française (from the Costumer's Manifesto)
