From The Art and Popular Culture Encyclopedia
Themis (Greek: Θέμις) is an ancient Greek goddess. She is described as "of good counsel", and is the embodiment of divine order, law, and custom. Themis means "law of nature" rather than human ordinance, literally "that which is put in place", from the verb τίθημι, títhēmi, "to put". To the ancient Greeks she was originally the organizer of the "communal affairs of humans, particularly assemblies". Moses Finley remarked of themis, as the word was used by Homer in the 8th century, to evoke the social order of the 10th- and 9th-century Greek Dark Ages:
Themis is untranslatable. A gift of the gods and a mark of civilized existence, sometimes it means right custom, proper procedure, social order, and sometimes merely the will of the gods (as revealed by an omen, for example) with little of the idea of right.
Finley adds, "There was themis—custom, tradition, folk-ways, mores, whatever we may call it, the enormous power of 'it is (or is not) done'. The world of Odysseus had a highly developed sense of what was fitting and proper."