Lego is a line of building toys manufactured by the Lego Group, a privately held company based in Denmark.
Its flagship product, commonly referred to as Lego bricks, consists of colorful interlocking plastic bricks and an accompanying array of gears, minifigures (also called minifigs by Lego fans), and various other parts. There are other Lego pieces which can be assembled and connected in many ways, such as cars, trucks, planes, trains, buildings, castles, sculptures, ships, spaceships, and even working robots.
Lego pieces of all varieties have been, first and foremost, part of a universal system. Despite tremendous variation in the design and purpose of individual pieces over the years, each remains compatible in some way with existing pieces. Lego bricks from 1963 still interlock with those made in 2007, and Lego sets for young children are compatible with those made for teenagers.
Bricks, beams, axles, mini figures, and all other elements in the Lego system are manufactured to an exacting degree of tolerance. When snapped together, pieces must have just the right amount of "clutch power"; they must stay together until pulled apart. They cannot be too easy to pull apart, or the resulting constructions would be unstable; they also cannot be too difficult to pull apart, since the disassembly of one creation in order to build another is part of the Lego appeal. In order for pieces to have just the right "clutch power", Lego elements are manufactured within a tolerance of 2 µm.
Since 1963, Lego pieces have been manufactured from a strong, resilient plastic known as acrylonitrile butadiene styrene, or ABS. Precision-machined, small-capacity molds are used, and human inspectors check the output of the molds, to eliminate significant variations in color or thickness. Worn-out molds are encased in the foundations of buildings to prevent their falling into competitors' hands. According to the Lego Group, about eighteen bricks out of every million fail to meet the standard required.
Manufacturing of Lego bricks occurs at a number of locations around the world. Molding is done at one of two plants in Denmark and Czech Republic. Brick decorations and packaging is done at plants in Denmark, United States, Mexico and the Czech Republic. Annual production of Lego bricks averages approximately 20 billion (2 × 1010) per year, or about 6000 pieces per second.
In 2006, Lego Group announced a restructuring of the current production setup including the outsourcing of some of the production work to Flextronics, a Singaporean electronics company. Lego Group plans to close the production facility in Enfield, Connecticut and outsource this work to the Flextronics factory in Mexico. Flextronics will also oversee the factory in Kladno, Czech Republic. The Czech facilities would also be expanded due to the planned closing of the Swiss factory in Baar, which mostly manufactured TECHNIC parts.
LEGO is officially written in all uppercase letters. The company asserts that to protect its brand name, the word Lego must always be used as an adjective, as in "LEGO set", "LEGO products", "LEGO universe", and so forth. Nevertheless, such corporate admonitions are frequently ignored and the word Lego is commonly used not only as a noun to refer to Lego bricks, but also as a generic term referring to any kind of interlocking toy brick.