labor union vs trades union

labor union and trades union both are nouns.

Word	Noun	Adjective	Verb	Adverb
labor union	Yes	No	No	No
trades union	Yes	No	No	No

As nouns, labor union and trades union are synonyms defined as:

labor union and trades union: an organization of employees formed to bargain with the employer

Other synonyms of labor union include brotherhood, trade union, union.

labor union (noun)	trades union (noun)
an organization of employees formed to bargain with the employer	an organization of employees formed to bargain with the employer