societo

English uses society for two quite different things and Esperanto refuses to. Societo is an organised body you can join - a club, an association, the local Esperanto group. Socio is society at large, the thing sociologists study. The adjectives follow: societa belonging to the club, socia social in the broad sense. Both roots sit in the core thousand precisely because the movement is built out of local societoj, and their names and reports fill a century of Esperanto periodicals.