Expense

The cost required to run a business is called expense. These include the routine expenses like salaries, commission, utility bills, etc.
OR
An expenditure, whose benefit is finished or enjoyed immediately or within the period of one accounting year, is called expense.
OR
The dollar amount of the resources used up by the firm during a particular period of time in the process of earning revenues.

Example

Salaries, Rent, Stationery, etc.