coupling in WordNet English dictionary

1. the act of pairing a male and female for reproductive purposes
   "the casual couplings of adolescents"; "the mating of some species occurs only in the spring"
   coupling  mating  pairing  conjugation  union  sexual union 
   
2. a mechanical device that serves to connect the ends of adjacent objects
   coupling  coupler 
   
3. a connection (like a clamp or vise) between two things so they move together
   yoke  coupling