From Bicycling.com:

Spencer Platt / Getty Images
A young girl chases the peloton along the route from Montargis to Gueugnon during Stage 6 of the 2010 Tour de France on July 9, 2010 in Gueugnon, France.
updated 1:46 p.m. ET June 22, 2011
Ever heard a word during a Tour broadcast and wondered, "What does THAT mean?" Here's every term that all cycling fans should know:
Aero bars: Special handlebars that allow a cyclist to ride in an aerodynamic tuck like a skier. Greg LeMond used them to dramatic effect in the 1989 Tour, winning by 8 seconds overall, and only on the final stage.
Alpe d'Huez: The most famous climb in the Tour, it's the most prestigious stage (21 switchbacks!) for any climber to win.
Attack: An aggressive, high-speed jump away from other riders.
Blocking: Legally impeding the progress of riders in the pack to allow teammates a better chance of success. (See also soft-pedaling).
Blow up: To suddenly be unable to continue at the required pace due to overexertion.
Bonk: This happens when you don't eat and drink enough; you run out of energy. Cyclists in the Tour take bags of food from their teams in the feed zones.
Bottom bracket: The cylindrical part of a bicycle frame that holds the crank axle, two sets of ball bearings, a fixed cup and an adjustable cup.
Break, breakaway: A rider or group of riders who have escaped the pack.
Bridge, bridge a gap: To catch a rider or group that has opened a lead.
Bunch: The main cluster of riders in a race. Also called the group, pack, field or peloton.
Bunny-hop: To jump over obstacles such as rocks or logs with both wheels off the ground at the same time. Roadies do this on the early stages of the Tour, when the race often goes through lots of towns with roundabouts. Nothing scarier than seeing a concrete barrier appear as the pack parts in front of you at 50 kph.
Cadence: The rate of pedaling, measured in revolutions per minute (rpm) of one foot. Lance Armstrong trained at a higher cadence beginning in 2003 and whooped everyone in his next three Tours.
Cassette: The set of gear cogs on the rear hub. Also called a freewheel, cluster or block.
Chain: A series of links pinned together that connects the chainwheel to the cogs on the back wheel and allows one to pedal the bike. (See also derailleur chains).
Chainring: A sprocket attached to the right crankarm to drive the chain.
Chainstays: The two tubes of a bicycle frame that run from the bottom bracket back to the rear dropouts.
Champs-Elysees: The famous street in Paris that the Tour finishes on. At one end is the Arc de Triomphe. Racers do three circuits of about 15 kilometers each. Speeds are incredibly fast (often averaging 35-40mph) as racers try to win this prestigious stage. Massive partying is commonplace, as are crashes.
Circuit: A road course that's ridden two or more times to compose the race.
Clincher Tire: A tire whose edges hook under the curved-in edge of a rim. Also known as "wired-on" tire.
Clipless Pedals: Pedals that use a releasable mechanism like that of a ski binding to lock onto cleated shoes and do not use toe clips or straps.
Cleat: A metal or plastic fitting on the sole of a cycling shoe that engages the pedal.
Clinchers: Conventional tires with a separate inner tube. (See also clincher tire).
Cog: A sprocket attached directly to the rear hub on a single-speed bike and mounted on a cassette on a multi-speed bike.
Crankarm: A part, one end of which is attached to the bottom bracket axle and the other holds a pedal,whose forward rotation provides the leverage needed to power the bicycle.
Criterium: A mass-start race covering numerous laps of a course about one mile or less in length. There are no criteriums as stages of the Tour, but many Tour riders do criteriums after the Tour for appearance money. August is crit season in Europe.
Derailleur: A lever-activated mechanism that pushes the chain off of one sprocket and onto another, thus changing the gear ratio.
Directeur Sportif: A French term essentially meaning head coach. The DS is responsible for planning team strategy for each stage and the overall race. He's usually the one directly answerable to sponsors too, so he operates as PR director, chief corporate liaison, head cook and bottle washer.
Doping: Originally meant in regards to blood doping, or withdrawing blood to re-inject it later on to boost red blood cell count and oxygen uptake. Now meant to include any performance enhancing substances, most of which are banned from competitive use and only some of which are testable.
Down Tube: The frame tube running from the headset to the bottom bracket, one part of the main triangle on a bicycle frame.
Drafting: Tucking in closely behind another rider so he/she'll break the wind, therefore saving you energy.
Drivetrain: The derailleurs, chain, freewheel, and crankset of a bike.
Dropped: To be left behind by the rest of the field. Also known as off the back or out the back.
Drops: The lower, straight portion of a turned-down-type handlebar.
Echelon: A form of paceline in which following riders angle away from the leader to get maximum draft in a crosswind.
Endo: To crash by going over the handlebar. Short for end-over-end.
Feed Zones: A designated point on a stage where team personnel called soigneurs can pass musettes of food and water bottles to riders. The food is often little pastries or finger sandwiches that the riders ask for; solid food is crucial during a multi-day race. There's always a huge group of kids waiting after the feed zones because riders toss away empty bottles and the musettes once they've gotten all the chow out of them.
Field Sprint: The dash for the finish line by the main group of riders. Also known as a bunch sprint or pack finish.
Full Tuck: An extremely crouched aero position used for maximum speed on descents.
General Classification (GC): The overall standings in a stage race.
Glycogen: A sequence of glucose molecules that forms the principal carbohydrate storage material in the body.
Green Jersey: The jersey given to the leader of the sprint points competition. Sprint points are gathered at pre-designated spots midway through certain stages, and at the end of select stages such as the finish on the Champs-Elysees. It was originally supposed to be for consistency of finishes, but is now widely termed "the sprinter's jersey."
Hammer: To jam, to go fast, usually uphill.
Hanging In: Barely maintaining contact at the back of the pack.
Headset: The parts at the top and bottom of the frame's head tube, into which the handlebar stem and fork are fitted.
Hors Categorie: French for "beyond category," a rating reserved for the stiffest climbs, such as the L'Alpe d'Huez and the Col du Galibier. Typical of the French, there's a guideline to how climbs are rated, but it's not set in stone. Rating relies on gradient, length, and position in a stage. Certain climbs, like the Alpe, are always beyond category. Other ratings, in decreasing order of difficulty are 1, 2, 3 and 4.
Intervals: A structured method of training that alternates relatively short, hard efforts with recovery periods of much easier riding.
Jam: A period of hard, fast riding.
Jump: A sudden acceleration.
King of the Mountains (KoM): A competition for the best climber, which runs on a points system like the green jersey. The leader wears the polka-dot jersey.
Lactic Acid: A by-product of anaerobic exercise that accumulates in the muscles, causing pain and fatigue.
Lanterne Rouge: The last rider in the field on general classification. The term, which means "red lantern," originated in the early days of the Tour, when a car bearing a red lantern would follow the last rider, signifying the back end of the race.
Leadout: A race tactic in which a rider accelerates to maximum speed for the benefit of a teammate in tow. The second rider then leaves the draft and sprints past at even greater speed to win the race or prime.
Le Tour: Any time a cyclist says, "le Tour," it's plain he or she is speaking of the Tour de France. No other race gets this treatment.
L'Equipe: The French sports daily. Used to be called l'Auto and was the chief sponsor of the Tour. Long ago gave rise to the yellow jersey idea. See Maillot Jaune.
Lieutenant: The team leader's right-hand man. The lieutenant helps keep the team organized during the stage and plans and executes strategy like chasing down breakaways or setting up the final sprint.
Liggett, Phil: A British chap and the best English-language television commentator on cycling. He's done commentary on the Tour for decades, and it's only through Phil's brilliance that we've lasted.
Maillot Jaune (yellow jersey): The race leader's jersey.
Mass Start: The criterion for events such as road races, in which all contestants leave the starting line at the same time.
Maximal Oxygen Consumption (VO2 max): The maximum amount of oxygen a person can consume in one minute. It is basically determined by heredity and a person's potential in endurance sports.
McQuaid, Pat: Current president of UCI.
Off-Camber Turn: The surface slopes sway from the curve, making it difficult and dangerous to go through with speed. If you thought these were only found in mountain biking, ride a Pyreneean pass sometime.
Off The Back (OTB): When one or more riders loses contact with the back end of the main pack.
Oxygen Debt: The amount of oxygen that needs to be consumed to pay back the deficit incurred by anaerobic work.
Paceline: A group formation in which each rider takes a turn breaking the wind at the front before pulling off, dropping to the rear position, and riding the others' draft until at the front once again.
Peak: A relatively short period during which maximum performance is achieved.
Peloton: The main group of riders in a race.
Prime: A special award given to the leader on selected laps during a criterium or track race, or the first rider to reach a certain landmark in a road race. It's used to heighten the action. Pronounced "preem." In the Tour, primes are points toward an overall competition, such as King of the Mountains or the sprinter's green jersey. Time bonuses are also given for the first three spots.
Prologue: A short stage that is held as the opener of the Grand Tours. It's usually less than 5 miles long, and is designed mainly as a showcase kick-off and a way to get the yellow jersey on someone's back right away. There are riders who are prologue specialists, whose goal it is to win the stage, and then defend the leader's yellow jersey for as long as possible in order to gain publicity for the team.
Publicity Caravan: An absolutely monstrous procession of vehicles that traces the day's route before the pack. Each tour sponsor has at least one vehicle, from which pretty girls toss everything from bags to newspapers and stickers and candy. The publicity caravan is bigger than the race itself in terms of personnel. One big rolling party.
Pull, Pull Through: Take a turn at the front.
Pull Off: To move to the side after riding in the lead so another rider can come to the front.
Road Rash: What happens to your skin when you crash. Really painful, and you get to scrape gravel out of the skin with a wire brush.
Rollers: An indoor training device that works like a treadmill for bikes. Also, a series of short hills. Tour riders use them to warm up prior to a stage.
Roundabouts: The nasty little traffic circles that are so popular in France and Belgium. They make life hell for racers as the pack goes screaming through some town at 55 kph and someone t-bones a concrete circle and breaks a collarbone.
Saddle Sores: Skin injuries in the crotch that result from chafing caused by pedaling action. Sores can range from tender raw spots to boil-like lesions if infection occurs.
SAG wagon: A motor vehicle that follows a group of riders, carrying equipment and lending assistance in the event of difficulty. Also called the broom wagon.
Slipstream: The pocket of calmer air behind a moving rider. Also called the draft.
Soft Pedal: To pedal without actually applying power. If a rider is in a solo break his teammates will break up the chase effort by soft-pedaling at the front of the pack to slow them down. If a racer in a break doesn't want to take his pull, he'll soft pedal.
Soigneur: French word meaning “to care for.†Soigneurs basically take care of anything that's not the directeur sportif's job (strategy, press conferences) or among the duties of the mechanics (working on the bikes). That means everything from finalizing hotel arrangements to assembling the day's feed bags, making sure riders have all their equipment, giving massages, doing laundry and countless other necessary, thankless tasks. They bust their butts for little money and no glory.
Stage: Each day's race during a multiple-race event is called a stage.
Stage Race: A multi-day event consisting of point-to-point and circuit road races, time trials, and, sometimes, criteriums. The winner is the rider with the lowest elapsed time for all stages.
Switchback: A 90-degree or greater turn. The 21 switchbacks of L'Alpe d'Huez is like cycling's equivalent of the frozen tundra of Lambeau Field.
Take a flyer: To suddenly sprint away from a group.
Team time trial (TTT): A race against the clock with two or more riders working together. There are no team-time trials in the 2006 Tour de France for the first time since 1999.
Time trial (TT): A race against the clock in which riders start at set intervals and cannot give or receive a draft. After finishing a time trial you should feel ready to puke. If you don't, you didn't ride hard enough. Racers use aerodynamic equipment like aero bars and special helmets that aren't allowed in mass-start stages.
Union Cycliste Internationale (UCI): The governing body of worldwide bike racing.
Yellow jersey: The race leader's jersey.