D defs.my
Entry 2 senses Webster, 1913

Coupling

/(-l?ng)/ · Coup·ling · IPA /ˈkʌplɪŋ/
01 n. The act of bringing or coming together; connection; sexual union.
  1. 1.
    The act of bringing or coming together; connection; sexual union.
  2. 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.