early 15c., "devoted to or relating to home life;" 1560s as "living with others," from French social (14c.) and directly from Latin socialis "of companionship, of allies; united, living with others; of marriage, conjugal," from socius "companion, ally," probably originally "follower," from PIE *sokw-yo-, suffixed form of root *sekw- (1) "to follow." Compare Old English secg, Old Norse seggr "companion," which seem to have been formed in Germanic on the same notion. Related: Socially.
It is attested by 1660s as "marked by mutual intercourse, enjoyed in the company of others," especially those of similar inclinations. Of a club, etc., "comprised of persons coming together for friendly intercourse," by 1792.
The broader sense of "living or liking to live with others; companionable, disposed to live in companies or communities" is from 1722. Social drinking "consumption of alcohol in a social context" is attested by 1807; social butterfly (1867) is a figurative reference to "flitting" from one social event to another. Social network is attested by 1971; social networking by 1984; social media by 2008.
The meaning "of or pertaining to society as a natural human state," and to its ranks and conditions, is attested by 1695 in Locke. Social contract (1763), the mutual agreement supposed to form the basis of human society, is from translations of Rousseau.
Hence also social science (1785). Social studies as an inclusive term for history, geography, economics, etc., is attested from 1916. Social security "system of state support for needy citizens" is attested from 1907 (the Social Security Act was passed by U.S. Congress in 1935).
And in reference to problems rooted in social conditions, social work (1890); social worker (1886). In late 19c. newspapers, social evil is "prostitution." Social justice is attested by 1718. Specifically of activities, especially by governments, meant to improve the condition of society overall, by 1964.
Social Darwinism "application of the theory of evolution to social situations" is attested from 1887. Social engineering, "application of sociology theory to specific problems" is attested by 1899.
The sense of "of or concerned with fashionable society and the leisured class" is from 1873. Hence social register "list of those who are socially prominent," attested by 1872 and used adjectivally by 1929 (e.g. "a social register crowd"); social climber, "one who seeks to advance socially" (1893).
Social distance was originally in a psychological sense in reference to societies (1924); it was used in reference to "physical distance acceptable in social situations" by 1955.
A social war (1660s) is one between allies, especially (with capitals) in reference to the Roman war 90-88 B.C.E. in which the Roman allies (socii) fought for citizenship rights.
I must introduce a parenthetical protest against the abuse of the current term 'social justice'. From meaning 'justice in relations between groups or classes' it may slip into meaning a particular assumption as to what these relations should be; and a course of action might be supported because it represented the aim of 'social justice', which from the point of view of 'justice' was not just. The term 'social justice' is in danger of losing its rational content—which would be replaced by a powerful emotional charge. I believe that I have used the term myself: it should never be employed unless the user is prepared to define clearly what social justice means to him, and why he thinks it just. [T.S. Eliot, footnote in "Notes Towards the Definition of Culture," 1948]
