What is "transfer window"

n. (context soccer English) A period of time in which soccer players may be bought or sold between professional clubs.

The transfer window is the period during the year in which a football club can transfer players from other countries into their playing staff. Such a transfer is completed by registering the player into the new club through FIFA. "Transfer window" is the unofficial term commonly used by the media for the concept of "registration period" as described in the FIFA Regulations on the Status and Transfer of Player. According to the rules, each national football association decides on the time (such as the dates) of the 'window' but it may not exceed 12 weeks. The second registration period occurs during the season and may not exceed four weeks.

The transfer window of a given football association governs only international transfers into that football association. International transfers out of an association are always possible to those associations that have an open window. The transfer window of the association that the player is leaving does not have to be open.

The window was introduced in response to negotiations with the European Commission. The system has been used in many European leagues before being brought into compulsory effect by FIFA during the 2002–03 season. English football was initially behind the plans when they were proposed in the early 1990s, in the hope that it would improve teams' stability and prevent agents from searching for deals all year around, but by the time it was eventually introduced they had to be persuaded that it would work. However, the exact regulations and possible exceptions are established by each competition's governing body rather than by the national football association.