What is the X in X-mas?
1530s, "companionship, friendly association with others," from Old French societe "company" (12c., Modern French société), from Latin societatem (nominative societas) "fellowship, association, alliance, union, community," from socius "companion" (see social (adj.)).
Meaning "group, club" is from 1540s, originally of associations of persons for some specific purpose. Meaning "people bound by neighborhood and intercourse aware of living together in an ordered community" is from 1630s. Sense of "the more cultivated part of any community" first recorded 1823, hence "fashionable people and their doings." The Society Islands were named 1769 by Cook on his third Pacific voyage in honor of the Royal Society, which financed his travels across the world to observe the transit of Venus.