Television (TV) is a telecommunication medium that is used for transmitting and receiving moving images and sound. Television can transmit images that are monochrome (black-and-white), in color or in three dimensions. Television may also refer specifically to a television set, television program or television transmission.First commercially available in very crude form on an experimental basis in the late 1920s, then popularized in greatly improved form shortly after World War II, the television set has become commonplace in homes, businesses and institutions, particularly as a vehicle for entertainment, advertising and news. During the 1950s, television became the primary medium for molding public opinion. In the mid-1960s, color broadcasting became popular in the US and began in most other developed countries. The availability of storage media such as VHS (1976), DVDs (1997) and high-definition Blu-ray Discs (2006) enabled viewers to use the television set to watch recorded material such as movies and broadcast material. In late 2000s, transition to digital television greatly increased its popularity. Since 2010s with arrival of smart television, Internet television has seen the rise of television programming available via the Internet through services such as Netflix, iPlayer, Hulu etc.In 2013, 79% of the world's households owned a television set. The replacement of bulky, high-voltage cathode ray tube (CRT) screen displays with compact, energy-efficient, flat-panel alternatives such as plasma displays, LCDs (both fluorescent-backlit and LED), and OLED displays was a major hardware revolution that began penetrating the consumer computer monitor market in the late 1990s and soon spread to TV sets in 2000s. In 2010s, most of the TV sets sold were flat-panel mainly LEDs. Major TV manufacturers announced the discontinuation of CRT, DLP, plasma and even fluorescent-backlit LCDs by mid 2010s. LEDs are expected to be gradually replaced by OLEDs in near future. Also, major manufacturers have announced to increasingly produce smart TV sets in mid 2010s. Smart TVs are expected to become dominant form of television by late 2010s.The television signals were initially distributed only as broadcast television or terrestrial television which is modeled on the radio broadcasting systems. Terrestrial television uses high-powered radio-frequency transmitters to broadcast the television signal to individual television receivers. In addition to the original terrestrial transmission method, television signals are also distributed by co-axial cable or optical fibre, satellite systems and Internet. Until the early 2000s, television signals were transmitted as analog signals but soon countries started switching to digital signals, with the transition expected to be completed worldwide by late 2010s.A standard television set is composed of multiple internal electronic circuits, including circuits for receiving and decoding broadcast signals. A visual display device which lacks a tuner is properly called a video monitor rather than a television.