Coupler

Coupler may refer to:

Mechanical

 * Railway coupler, a mechanism for connecting rolling stock on a train
 * Janney coupler
 * SA3 coupler
 * Scharfenberg coupler for multiple unit passenger cars
 * Quick coupler, used in construction machines to allow the rapid change of buckets
 * Coupling, a device used to connect two shafts together at their ends for the purpose of transmitting power
 * Universal coupling, a joint or coupling in a rigid rod that allows the rod to 'bend' in any direction

Electronics

 * Acoustic coupler, for coupling electrical signals by acoustical means
 * Directional coupler, a passive device used in radio technology
 * Antenna coupler, a device connected between a radio transmitter or receiver and its antenna
 * Output coupler, a partially reflective mirror used in lasers
 * Optocoupler, an electronic component that transfers electrical signals between two isolated circuits by using light

Other uses

 * Coupler (piping), also called a (joist) short length of pipe with two female threads
 * 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
 * Coupler, a tap valve, for controlling the release of beer out of a keg
 * Coupler, the floating link in a four-bar linkage
 * Hydrant coupler, for aircraft fueling equipment