trades union vs labor union

trades union and labor union both are nouns.

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

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

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

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

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