Maillot jaune (French for yellow jersey, pronounced 'my-oh jhohn') is the jersey worn by the current overall leader of many bicycle races, originally and most notably the Tour de France. It allows the rider who was in the overall lead at the end of the previous day to be easily identified during the race.
The overall leader is the one with the lowest cumulative time for the race so far, minus any time bonuses, plus any time penalties. It is therefore theoretically possible, though unlikely, for the final overall winner to take first place only on the last stage of an event, and thus not have worn the maillot jaune until they are awarded it on the final podium. In fact, this has happened in two Tours—the 1947 (Jean Robic) and 1968 (Jan Janssen) editions. Greg LeMond nearly duplicated this feat in his last Tour win in 1990, as he did not earn the maillot jaune until the next-to-last day of the Tour. (In his legendary 1989 win, when he took yellow on the final day, he had won and lost the jersey earlier in the Tour.)
The time bonuses are awarded for finishing in the top of the stages and in certain designated sprints within stages.
The decision to designate the time leader in this way, was made by Tour founder Henri Desgrange partway through the 1919 Tour de France, and it was first worn by Frenchman Eugène Christophe in the stage from Grenoble to Genève. The colour was chosen to reflect the yellow newsprint on which the newspaper L'Auto (later L'Équipe) - the chief sponsor of the event - was printed. It also featured the stylised initials 'HD' (for 'Henri Desgrange') which were removed in 1984 to make way for sponsorship, but re-added to the shoulders of the jersey in 2003 as part of the Tour's centenary celebrations. One set of initials is now worn on the upper right chest of the jersey.
Since 1931, the overall leader in the Giro d'Italia (Tour of Italy) is awarded the maglia rosa (pink jersey), also reflecting the paper colour of the sports newspaper (La Gazzetta dello Sport) originally sponsoring the race. The leader in the Vuelta a España (Tour of Spain) wears a "golden jersey".