Turnbuckle vs. Coupler — What's the Difference?

A turnbuckle, stretching screw or bottlescrew is a device for adjusting the tension or length of ropes, cables, tie rods, and other tensioning systems. It normally consists of two threaded eye bolts, one screwed into each end of a small metal frame, one with a left-hand thread and the other with a right-hand thread.

One that couples, especially a device for coupling two railroad cars.

A metal coupling device consisting of an oblong piece internally threaded at both ends into which the corresponding sections of two threaded rods are screwed in order to form a unit that can be adjusted for tension or length.

A device connecting two organ keyboards so that they may be played together.

A coupling device consisting of two eyelets or other connection points connected in screw threads. The joint in between can be turned to shorten or lengthen the device with mechanical advantage provided by the screw threads.

Someone who couples things together, especially someone whose job it is to couple railway carriages.

(nautical) A link threaded on both ends of a short bar which is used to pull objects together. (FM 55-501)

Anything that serves to couple things together; but especially a device that couples railway carriages.

(music) A device that connects two keyboards of an organ together so that they play together.

A device used to convert electronic information into audible sound signals for transmission over telephone lines.

An electrical device used to transfer energy from one electric device to another, especially without a physical connection.

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

A mechanical device that serves to connect the ends of adjacent objects