A coupling (or a coupler) is a mechanism for connecting rolling stock in a train. The design of the coupler is standard, and is almost as important as the track gauge, since flexibility and convenience are maximised if all rolling stock can be coupled together.
Bow may refer to:
Bow and arrow (), a weapon system that uses elasticity to propel arrows, its use is archery
Bow (ship) (), the foremost point of the hull of a ship or boat