A nuclear family or elementary family is a family group consisting of a pair of adults and their children. This is in contrast to a single-parent family, to the larger extended family, and to a family with more than two parents. Nuclear families typically centre on a married couple; the nuclear family may have any number of children. There are differences in definition among observers; some definitions allow only biological children that are full-blood siblings, while others allow for a stepparent and any mix of dependent children including stepchildren and adopted children.

Family structures of one married couple and their children were present in Western Europe and New England in the 17th century, influenced by church and theocratic governments. With the emergence of proto-industrialization and early capitalism, the nuclear family became a financially viable social unit. The term nuclear family first appeared in the early twentieth century. Alternative definitions have evolved to include family units headed by same-sex parents, and perhaps additional adult relatives who take on a cohabiting parental role; in this latter case it also receives the name of conjugal family.

¡Uno! is the ninth studio album by the American punk rock band Green Day, released on September 21, 2012, by Reprise Records. It is the first of three albums in the ¡Uno!, ¡Dos!, ¡Tré! trilogy, a series of studio albums released from September 2012 to December 2012. Green Day recorded the album from February to June 2012 at Jingletown Studios in Oakland, California. It is the band's first album as a quartet, as Jason White became an official member.

Artwork of the album was revealed in a video uploaded to YouTube and the track list of the album, which consist of 12 songs was announced on June 26, 2012. The first single from the album, titled "Oh Love", was released on July 16, 2012. The second single "Kill the DJ" was released on European iTunes Stores on August 14, 2012. The third single "Let Yourself Go" was released on the US iTunes Store on September 5, 2012, and a promotional single "Nuclear Family" was released on their YouTube channel on September 12, 2012. A music video for "Stay the Night" was released on Rolling Stone and their YouTube channel on September 24, 2012.