Jersey: A bicycling shirt with pockets in the back, often decorated with team colors and sponsors' logos. Special colored jerseys in races such as the Tour de France denote the leader in a certain category.
Jump: A quick acceleration.
Kick: A burst of acceleration for the final sprint.
KOM: King of the Mountains. Award for the best climber.
Lactic, lactic acid: Describes the byproduct in the muscles that causes the burning sensation after strenuous physical exertion.
Lead out: A sacrificial race tactic in which you allow a teammate to draft immediately behind you ("on your wheel") as you accelerate to high speed, to give them a head start for their own impending attack or sprint.
Mechanical: Slang for a mechanical problem with the bicycle.
Neutral support: The support given to a rider by a neutral party, i.e. a mechanic in a follow vehicle not attached to any particular team.
Off the back: When a rider or riders cannot keep pace with the main group and lag behind.
Off the front: When a rider, or group of riders, break away from the main group.
On the rivet: Riding very hard. (Some old leather bike saddles had a rivet on the nose of the saddle, and you tend to sit closer to the nose when pedaling very hard.)
Paceline: A string of riders moving at high speed, with individuals taking turns setting the pace at the front and then dropping back into the draft of the others.
Palmares: A rider's race results during their career. ("He has an impressive palmares.")
Parcours: French for "the race course."
Peloton: The main group of riders in a race; also called the pack, bunch or field. Can also refer to pro cyclists collectively: "He's respected in the peloton."
Prologue: A short time trial held on the first day of a stage race, before Stage 1.
Pull: To take a turn at the front of the group or paceline.
Pull off: To move out of the front position in a group or paceline, so that a following rider can take over.
Puncture: Flat tire.