Opex and Operating expense

Operating expense and opex are semantically related. In some cases you can replace phrase "Operating expense" with "Opex", this terms are similar.

Operating expense 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.

Opex and operating expense are semantically related. You can use "Opex" instead a noun phrase "Operating expense".