operating expense

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An expense incurred in normal business operations, such as an administrative or selling expense.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun business, accounting Any expense incurred in running a business, such as sales and administration, as opposed to production.
• noun business, accounting The money an entity spends in order to turn inventory into throughput.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the expense of maintaining property (e.g., paying property taxes and utilities and insurance); it does not include depreciation or the cost of financing or income taxes