tax vs operating cost

tax and operating cost both are nouns.

Word	Noun	Adjective	Verb	Adverb
tax	Yes	No	Yes	No
operating cost	Yes	No	No	No

tax (noun)	operating cost (noun)
charge against a citizen's person or property or activity for the support of government	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

tax (verb)	operating cost (verb)
make a charge against or accuse
use to the limit
levy a tax on
set or determine the amount of (a payment such as a fine)