What is "OPEX" ?

An operating expense, operating expenditure, operational expense, operational expenditure or Opex is an ongoing 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 involves Capex, and the annual paper, toner, power and maintenance costs represents Opex. For larger systems like businesses, Opex may also include the cost of workers and facility expenses such as rent and utilities.

OPEX stands for "OPerating EXpenses". These are expenses related to the operating activities of the entity.

As mentioned by our collegues OPEX is an abbreviation of Operating Expenses or Expenditures, that results from the ongoing cost incurred by the company to run its business. 

It is operating expense which company incur to run Its principal business

Thank you for the invitation ... I agree with colleagues Answers

thanks for the invitation

it is ( operating expenditure)

is ongoing costs which the company spend it on business 

for example ( rent of the factory - Machine maintenance .....)

is an expense a business incurs through its normal business operations. Often abbreviated as OPEX, operating expenses include rent, equipment, inventory costs, marketing, payroll, insurance and funds allocated toward research and development. One of the typical responsibilities that management must contend with is determining how low operating expenses can be reduced without significantly affecting a firm's ability to compete with its competitors.

Agree on experts opinion, 

just will try to cover it with different perspective;

The Expired portion of cost or asset allowable to charge P&L account are companies Operational expenses the cut of line between OPEX and CAPEX is time span usually one year, i.e if the expenditures or cost that have useful life more than one year ( expected inflow of benefits last for more than one year) it is categorized as Capital expenditure(PP&E IAS 16) under investment activities while cost that does not become expired at the point of incurring but  also not last more than one year (like inventory IAS 2).

some time it is difficult to draw a line between OPEX and CAPEX. we need to use judgment and often apply the concept of materiality in order to make a conclusion.

As per my understanding the Simple formula is Expired portion of Cost is your expense. 

Regards,

An operating expense, operating expenditure, operational expense, operational expenditure or Opex is an ongoing cost for running a product, business, or system. 

An operating expense

that results from the ongoing costs a company pays to run its basic business operationsoperating expenses are fully tax-deductible in the year they are made. As operational expenses make up the bulk of a company's regular costs