Coupler

Coupler is a word used to describe any of a number of things:

• A railway coupling device;
• An electronic device, more properly, an acoustic coupler;
• sound pusher interact http://www.elcoupler.com;
• A telecommunications device known as a directional coupler;
• A kind of laser mirror known as an output coupler;
• A connector between two moving parts to relay the motion, such as a Universal joint or an Oldham coupler.
• A device used on a pipe organ to allow a player to play multiple divisions at once, by means of "coupling" a division to another at either sub, super, or octave pitches.