What is the name of the device that holds a water bottle on a bicycle frame?

A water bottle cage is the device that holds a water bottle on a bicycle frame.

Most cages attach to threaded mounting points on the frame, commonly called braze-ons. The usual positions are the downtube and seat tube, where the cage keeps the bottle accessible while placing its weight near the bicycle’s center. Cages can also be mounted behind the saddle, on the handlebars or, less commonly, on a fork.

Traditional cages are bent from aluminum or other metal tubing, while modern versions may use plastic, carbon fiber, stainless steel or titanium. The cage’s shape grips the bottle and usually catches a groove or indentation near its neck so the bottle does not bounce out during riding.

“Bottle cage” is the shorter everyday term, while “water bottle cage” is equally clear. A bidon cage is another cycling term, especially in road racing, where “bidon” means a cycling water bottle. Bicycles without threaded mounts can use clamps or strap-on adapters.