(to cause things) to become united as one (physical) thing
combine, link
Cases of word usage
1) a device used to connect one or more electrical plugs to a socket (adapter)
2) a set of toothed wheels working together in a machine, e.g. to connect the engine of a vehicle with the road wheels (gear)
3) a container; a place (usually in the wall) where one may connect an electrical appliance to the electrical circuit (receptacle)