Nuclear family entered English dictionaries in the 1920s
Also called an elementary, atomic, or conjugal family, the nuclear family groups two parents with their children—sometimes only full biological siblings, sometimes adoptees too. Merriam-Webster dates the English term to 1924; many anthropologists still see extended kin as historically more common.
In everyday use it means a household of mother, father, and children under one roof. Observers disagree whether stepchildren or half-siblings count, so census categories and sociology textbooks rarely match perfectly. The Oxford English Dictionary has an example from 1925, and the word nucleus behind the name goes back to Latin nux, a nut, meaning the core of something.
George Murdock's early description stressed shared residence, economic cooperation and reproduction. Most people belong to two such units in a lifetime, the family they are born into and the one they raise, and newer definitions take in same-sex parents and adoptees. DNA from a 4,600-year-old Stone Age burial in Germany gives the earliest archaeological evidence of two parents with several children; Wolfgang Haak of Adelaide University analysed a 2005 dig at Elau in which 13 people in one grave proved closely related. Historians Alan Macfarlane and Peter Laslett argue nuclear households have dominated in England since the thirteenth century, unlike Southern Europe, parts of Asia and the Middle East.
Proto-industrialization and early capitalism made the unit financially workable. In 2005 US Census data showed 70 percent of American children in two-parent homes, and in 2000 households with both original biological parents made up about 24.10 percent of the total. In the UK the share fell from 39.0 percent of households in 1968 to 28.0 percent in 1992, as single parents and people living alone increased. Housing, medical and education costs have climbed sharply since the 1950s, and studies in the West and India find single nuclear households tend to have more children than co-operative living arrangements.
Source: Nuclear family
