From Latin 'collocāre' (to lay in place), via Old French 'couche' (bed) — originally a lying-down surface, later a sitting one.
A long upholstered piece of furniture for several people to sit on.
From Old French 'couche' meaning 'a bed, lair,' from 'coucher' (to lie down), from Latin 'collocāre' meaning 'to lay in place,' from 'com-' (together) + 'locāre' (to place). Key roots: locāre (Latin: "to place").