A track for cycle racing, or, more properly, the building or facility that houses such a track.
The earliest track or "path" racing in the late 1800s took place on the cinder or shale running tracks of the time, but with the increasing popularity of the sport, concrete or asphalt tracks were laid; increasing speeds meant that the bends were banked to give the "bowl" effect that is still familiar today, although the sizes and proportions varied widely; the track in the stadium at White City built for the 1908 Olympic Games was half a mile (800m) per lap. The commonest pattern, however, was for a track to be built around the outside of a 400 metre or 440 yard running track and/or a football or rugby field, giving lap distances of 460 metres or so. Banking angles varied greatly up to around 30 degrees. Many had direct road access onto the track so that they could also be used for the finishes of road races (Before its move to the Champs Elysées the Tour de France finished at the velodrome in the Bois de Vincennes, while Paris-Roubaix still finishes this way).
Around the same time indoor tracks were built for all-weather use and the then popular six-day races. A few venues such as Madison Square Gardens, the Vélodrome d'Hiver in Paris and the Antwerp Sportpaleis had permanent structures, but many other events were run in exhibition halls on temporary wood tracks; without the need to fit around other field sports and with building size limits, the board tracks were generally much shorter, with a practical minimum of about 160 metres or a tenth of a mile; bankings were perforce much steeper, giving a "wall of death" effect with angles of between 45 and 60 degrees, with the straights being banked too to give a smooth transition.
Although many of the big old outdoor tracks around the world continue to be used for local events, the focus has now shifted to covered tracks for all major races, with the UCI only authorizing top flight competition - World Championships, the Olympics and continental games, and World Cup meets - on indoor tracks of 250m or 333.33m; the last outdoor World Championships were those held in Bogotá in 1995. There are around 800 velodromes around the world and new tracks, both permanent and temporary, are still being built - the leading specialist is Britain's Ron Webb - now using computer aided designs with asymmetric bankings (shallower entrances to the bends and steeper exits make for faster riding. The favoured material for the surface is Siberian pine, carefully selected to be splinter free.
Tracks of all shapes and sizes use standard markings. Inside the track proper an area known as the "blue band" (a rather prosaic rendering of the French "Côte d'Azur") serves as a smooth transition into the flat safety area around the track centre, which serves as a riders' rest area and in some cases additional spectator accommodation (track centre restaurants with silver service are something of a tradition on the six-day circuit); a black or white measuring line marks the inside line of the track proper (for timed events like pursuits and the kilo the area inside the timing line is blocked off using foam pads that will not cause riders to crash but will slow them down); 50 cm further up the track is the red sprinter's line which marks the point at which it is generally not permissible to pass a rider on the inside, and two metres further up the blue stayer's line performs the same purpose for motor-paced races. Radial markings denote the finish line (obviously), the start and finish stations for pursuits and the 200 m to go point (the final 200 metres is timed in the match sprint). The race jury members occupy a stand on the inside of the track at the finish line, while a referee views independently from outside the track to take instant decisions on disqualifications for dangerous riding or other such breaches of the rules.