microcosm (n.)

late 12c., mycrocossmos (modern form from early 15c.), "human nature, man viewed as the epitome of creation," literally "miniature world," from Medieval Latin microcosmus, from Greek mikros "small" (see micro-) + kosmos "world" (see cosmos).

General sense of "a community constituting a world unto itself, a little society" is attested from 1560s, perhaps from Middle French microcosme. A native expression in the same sense was petty world (c. 1600).

Forrþi mahht tu nemmnenn mann Affterr Grikkishe spæche Mycrocossmos, þat nemmnedd iss Affterr Ennglisshe spæche Þe little werelld. ["Ormulum," c. 1175]