Operating Expenses

costs involved in operation, costs required to be active

An operating expense, operating expenditure, operational expense, operational expenditure or OPEX is an on-going cost for running a product, business, or system. Its counterpart, a capital expenditure (CAPEX), is the cost of developing or providing non-consumable parts for the product or system. For example, the purchase of a photocopier is the CAPEX, and the annual paper and toner cost is the OPEX. For larger systems like businesses, OPEX may also include the cost of workers and facility expenses such as rent and utilities.
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all the costs incurred by a firm in carrying out its day-to-day activities.

Expenses incurred in the performance of air transportation, based on overall operating revenues and overall operating expenses. Does not include nonoperating income and expenses, nonrecurring items or income taxes. (BTS4)

The costs of handling traffic, including both direct costs, (such as driver wages and fuel) and indirect costs (e.g. computer expenses and advertising) but excluding interest expense. (ATA2)

Expenses of furnishing transportation service including the expense of maintenance and depreciation of the plant used in the service. (AAR1)