What is an office?
An office is generally a room or other area in which people work, but may also denote a position within an organisation with specific duties attached to it (see officer, office-holder, official); the latter is in fact an earlier usage, office as place originally referring to the location of one's duty. When used as an adjective, the term office may refer to business-related tasks. In legal writing, a company or organization has offices in any place that it has an official presence, even if that presence consists of, for example, a storage silo rather than an office.
An office is an architectural and design phenomenon and a social phenomenon, whether it is a tiny office such as a bench in the corner of a "Mom and Pop shop" of extremely small size (see small office/home office) through entire floors of buildings up to and including massive buildings dedicated entirely to one company. In modern terms an office usually refers to the location where white-collar workers are employed.
For more details, please see from http://en.wikipedia.org/wiki/Office