license fee vs license tax

license fee and license tax both are nouns.

Word	Noun	Adjective	Verb	Adverb
license fee	Yes	No	No	No
license tax	Yes	No	No	No

As nouns, license fee and license tax are synonyms defined as:

license fee and license tax: a fee paid to the government for the privilege of being licensed to do something (as selling liquor or practicing medicine)

Other synonyms of license fee include licensing fee.

license fee (noun)	license tax (noun)
a fee paid to the government for the privilege of being licensed to do something (as selling liquor or practicing medicine)	a fee paid to the government for the privilege of being licensed to do something (as selling liquor or practicing medicine)