Commercial photography is probably one of the widest and broadest photography types and can refer to many related disciplines. Generally speaking, commercial photographers are photographers who's images are used to promote business, products and services.
For example, wedding photographers are not commercial by nature as their photos are for personal use. Portrait photographers can be both commercial or personal.
A few photoshoot types that are covered by commercial photography include
As opposed to other types of photography, commercial photography is very hard to pin down. The one overall common thread with most commercial photographers is that they create photos that help sell and grow business revenue by looking clean, clear and having a wide appeal with audiences.