Coupling

Webster's Dictionary of the English Language

·p.pr. & ·vb.n. of Couple.

II. Coupling ·noun The act of bringing or coming together; connection; sexual union.

III. Coupling ·noun 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.