The following article was sourced from a Wikipedia page at the following address: http://en.wikipedia.org/wiki/Sport_coat
A sport coat, also called a sports coat, sports jacket, tweed jacket, or tweed coat, less commonly known as a sportcoat, is a jacket for men. Though it is of a similar cut and length to a suit jacket, there are several differences. First, a sport coat may be worn on less formal occasions than a suit would be. Also, it is designed to be worn on its own, without matching trousers, and does not come as part of a suit. Styles, fabrics, colours and patterns are also more varied than in most suits; sturdier and thicker fabrics may be used, such as corduroy, suede, denim, leather, and tweed.
Originally, sports coats were worn as casual attire for hunting and other outdoor sports (hence the name). With time, they came to be used on more formal occasions, sometimes being used in school uniforms.
A shooting jacket is a type of sports coat worn, as the name suggests, originally in the sports of shooting or hunting. It usually comes with a leather patch on the front shoulder to prevent recoil wear from the butt of a shotgun or rifle, frequently with matching leather patches on the elbow.
A hacking jacket is a wool sports coat for casual horseback riding, often of tweed and traditionally 3 buttoned with a single vent.
A blazer is similar to a sports coat, and is tailored from solid colour or striped fabrics. Blazers are often made with metal buttons reflecting their origins in the sport of boating, though this is not necessarily a defining feature. Blazers also often have patch pockets, unlike other kinds of coats.
To read more about sport coats, please click on the following link: http://en.wikipedia.org/wiki/Sport_coat