car·a·bi·ner also kar·a·bi·ner 
(kăr′ə-bēnər)
(kăr′ə-bēnər)n.
An oblong metal ring with a hinged and spring-loaded gate, used in activities such as mountaineering to connect a running rope to another piece of equipment.
[German Karabiner, short for Karabinerhaken, hook for a carbine, from Karabiner, carbine, from French carabine; see CARBINE.]
carabiner