420

420 may refer to:

Science and technology

 * 420 (number), in mathematics
 * 420 Bertholda, a main-belt asteroid
 * 4:2:0, a chroma subsampling layout

Cannabis culture

 * 420 (cannabis culture), informal reference to cannabis use and celebrations on April 20
 * California Senate Bill 420 or the Medical Marijuana Program Act
 * "420" (Family Guy), an episode of Family Guy
 * "4-2-0" (song), a song by Kottonmouth Kings from Rollin' Stoned

Dates

 * AD 420, a year in the 5th century of the Julian calendar
 * 420 BC, a year
 * April 20

Other uses

 * 4-2-0, a classification of steam locomotives
 * 420 (dinghy), a class of double-handed racing sailboats
 * "4:20", a song by Six Feet Under on the 1997 album Warpath
 * Section 420 of the Indian Penal Code, a law against cheating and dishonesty
 * +420, calling code of Czech Republic