trade union
noun /ˌtreɪd ˈjuːniən/
  /ˌtreɪd ˈjuːniən/
 (also union)
 (British English also trades union, North American English also labor union)
- an organization of workers, usually in a particular industry, that exists to protect their interests, improve conditions of work, etc.Topics Businessb1, Working lifeb1