Coupler

n. one that joins; one that mates; one that attaches

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;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 or harpsichord 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.A valve, specifically a tap, for controlling the release of beer out of a keg.A sound artist www.elcoupler.com
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Noun
1. a mechanical device that serves to connect the ends of adjacent objects
(synonym) coupling
(hypernym) mechanical device
(hyponym) clevis
(derivation) couple, couple on, couple up

v. couple

(n.)
One who couples; that which couples, as a link, ring, or shackle, to connect cars.