= sense 1a(d).

A thing that couples or links together. spec. In an organ: A contrivance for connecting two manuals, or a manual with the pedals, or two keys an…

A coupler, n. in the organ.

= pedal-coupler n.

A type of octave coupler used with a keyboard instrument. Obsolete. rare.

a device in an organ, etc., enabling a note an octave higher or lower to be sounded with the note being played.

see quots.

a unison manual coupler in an organ in which the connection between each two keys is made by a short sticker (see 13f) which turns over at an angle…

a form of coupler used to link closely set organ manuals so that they can be played in a single motion.

Technical and scientific uses; in Machinery, etc., the name of various contrivances for connecting… In an organ; = coupler, n.