Coupling /(-l?ng)/

Coup·ling

Coupling

n.
  1. The act of bringing or coming together; connection; sexual union.
  2. A device or contrivance which serves to couple or connect adjacent parts or objects; as, a belt coupling, which connects the ends of a belt; a car coupling, which connects the cars in a train; a shaft coupling, which connects the ends of shafts. (Mach.)

Phrases & Compounds
Box coupling
See under Box, Chain.
Coupling box
a coupling shaped like a journal box, for clamping together the ends of two shafts, so that they may revolve together.
Coupling pin
a pin or bolt used in coupling or joining together railroad cars, etc.