union 5 Posted in U Best definition union 5 A 5 min break from any event or activity that is mandatory to take. Derived from Union contracts that factor in breaks for Union workers. Hey after we’re done draining this pool lets take a Union 5. How satisfied are you with the definition? Looking for union 5 meaning? Delighted that you discovered the greatest determine on our web site! Recently this definition was actually observed 19 times.