For other cycling related terms (besides parts) see Glossary of cycling.
List of bicycle parts by alphabetic order:
Axle: as in the generic definition, a rod that serves to attach a wheel to a bicycle and provides support for bearings on which the wheel rotates. Also sometimes used to describe suspension components, for example a swing arm pivot axle Bar ends: extensions at the end of straight handlebars to allow for multiple hand positions Bar plugs or end caps: plugs for the ends of handlebars Basket: it is an optional attachment on a bike and is used for carrying things Bearing: a device that facilitates rotation by reducing friction Bell: an audible device for warning pedestrians and other cyclists Belt-drive: alternative to chain-drive Bicycle brake cable: see Cable Bottle cage: a holder for a water bottle Bottom bracket: The bearing system that the pedals (and cranks) rotate around. Contains a spindle to which the crankset is attached and the bearings themselves. There is a bearing surface on the spindle, and on each of the cups that thread into the frame. The bottom bracket may be overhaulable (an adjustable bottom bracket) or not overhaulable (a cartridge bottom bracket). The bottom bracket fits inside the bottom bracket shell, which is part of the bicycle frame Brake: devices used to stop or slow down a bicycle. Rim brakes and disc brakes are operated by brake levers, which are mounted on the handlebars. Band brake is an alternative to rim brakes but can only be installed at the rear wheel. Coaster brakes are operated by pedaling backward Brake lever: a lever for actuating a bicycle brake Brake shifter or colloquially, brifter (see also Shimano Total Integration, Campagnolo ErgoPower and SRAM Double Tap): combined shifter and brake lever control Braze-on: a fitting protruding from a frame to provide attachment, typically for cable housings or tire pumps and similar accessories Cable guide: a fitting below the bottom bracket which guides a piece of bare inner bowden cable around a corner Cable: a metal cable enclosed in part by a metal and plastic housing that is used to connect a control, such as a brake or shifting lever, to the device it activates Cartridge bearing: a type of bearing that is not user-serviceable, but must be replaced as a unit Cassette: a group of stacked sprockets on the rear wheel of a bicycle with a rear derailleur Coaster brake or backpedal brake Chain: a system of interlinking pins, plates and rollers that transmits power from the front sprocket(s) to the rear sprocket(s) Chainguard: Gear case cover for the entire chain either totally encasing (sometimes containing oil) or 'incomplete'. Either way, designed to keep clothing from fouling the chain. See also Skirtguard, Bashguard. Chainring: (one of the) front gear(s), attached to a crank Chainset: see Crankset Chainstay: a pair of tubes on a bicycle frame that runs from the bottom bracket to the rear fork ends Chain tensioner: a device to maintain proper chain tension Chaintug: a device to aid in setting the proper chain tension Cluster: a bicycle cogset, either a freewheel, or cassette Cogset: the set of rear sprockets that attaches to the hub on the rear wheel Cone: holds bearings in place, pressed against the cup Cotter: pin for attaching cottered cranks Coupler: to connect tubing together Crankset or chainset: composed of cranks and at least one chainring Cup: receives ball bearings which roll along its inner surface; integrated on most conventional hubs or can be pressed into older bottom bracket shells. See also Cone Cyclocomputer: an electronic accessory that measures and displays instantaneous and cumulative speed and distance. Often provides other measurements such as heart rate Derailleur: an assembly of levers, usually cable-actuated, that moves the chain between sprockets on a cassette or chainring assembly Derailleur cage: the part of the Rear derailleur that holds the Pulley wheels Derailleur hanger: a piece on the rear dropout that the derailleur attaches to. Down tube: tube on the bicycle frame that runs from the head tube to the bottom bracket Dropout: a bicycle rear fork end that allows the rear wheel to be removed without first derailing the chain. The term dropout is often incorrectly used to refer to any fork end, but not all fork ends are dropouts Dustcap: any cap serving to keep dirt and contamination out of an assembly. Common over crank bolts, often plastic Dynamo: bicycle lighting component, also known as generator Eyelet: 1) attachment point on frame, fork, or dropout for fenders, racks, etc.