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Webster 1913 Edition
Coupler
Coup′ler
(k?p′l?r)
, Noun.
One who couples; that which couples, as a link, ring, or shackle, to connect cars.
Coupler of an organ
, a contrivance by which any two or more of the ranks of keys, or keys and pedals, are connected so as to act together when the organ is played.