1. a thing that connects two things, especially mechanical components or systems: "a hydraulic coupler"
▪ a device in an organ for connecting two manuals, or a manual with pedals, so that they both sound when only one is played.
▪ a device in an organ for connecting notes with their octaves above or below.
▪ a compound in a developer or an emulsion which combines with the products of development to form an insoluble dye, part of the image.
▪ a modem which converts digital signals from a computer into audible sound signals and vice versa, so that the former can be transmitted and received over phone lines.
