The Back office reference article from the English Wikipedia on 24-Jul-2004
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Back office

Sponsorship the way you would do it
A back office is a part of most corporations where tasks dedicated to running the company itself take place. Examples of back-office tasks include IT departments that keep the phones and computers running, accounting and human resources.

The term comes from the building layout of early companies where the front office would contain the sales and other customer-facing staff, and the back office would be those manufacturing or developing the products or involved in administration but without being seen by customers.