A window is defined as an opening, usually covered clear glass, in an shop which allows people to view the shop and its product from outside (Wiktionary).
The first recorded use of plate-glass store windows is in 1909 by Gordon Silfriges in London where window lights were left on at night to allow people see the presentation even if the store is close.
Nowadays, different types of windows are coming out. They vary from sizes, purpose and location, and the term store window or display window do not necessarily refer to an opening in front of the store or on the any side of the store.
Types of Store Windows:
1. Closed Windows: Large glass panel at the front and solid wall at the back.
Photo: Mount Juneau Trading Post by Patrick Harvey, on Flickr
2. Semi-closed Windows: Large glass panel at the front and half-covered at the back so that the inside of the store is partially visible.
Photo: J.Crew West Edmonton Mall by Darrell, on Flickr
3. Open-back Windows: Large glass panel at the front and no wall at the back
Photo: GANT by Angela Song 2012, on Flickr
4. Open Window (or No Window): No glass panel and no solid wall.
Photo: ExpressMen West Edmonton Mall by Darrell, on Flickr
5. Elevated Windows: It can either be closed or open window that is located in a higher level.
Photo: 有创意！(Creative) by Angela Song 2012, on Flickr
6. Corner Windows: Windows that are located at the corner of the building and are seen from two directions.
Photo: Outside and in by Roving I, on Flickr
7. Island Windows: These are the stand-alone windows that are often located at the lobby of a big store.
Photo: Island window display via Designboom.
8. Shadow Boxes: Small box-like windows that are usually used for jewelry and cosmetics displays.
Photo: LOUIS VUITTON display via Delicious Magazine