wage increase vs salary increase

wage increase and salary increase both are nouns.

Word	Noun	Adjective	Verb	Adverb
wage increase	Yes	No	No	No
salary increase	Yes	No	No	No

As nouns, wage increase and salary increase are synonyms defined as:

Other synonyms of wage increase include hike, raise, rise, wage hike.

wage increase (noun)	salary increase (noun)
the amount a salary is increased	the amount a salary is increased