means A rule or system of rules recognized and enforced by a society to govern conduct, with consequences for breaking it.

from From Old English 'lagu,' itself borrowed from Old Norse 'lǫg' — literally 'something laid down or fixed,' the plural of 'lag,' meaning a layer or that which is placed. So at its root, a 'law' is simply what has been set in place, related to the verb 'to lay.' The Norse seafarers and settlers handed England this word, edging out the native Old English 'ǣ.' Note the cousin idea in Latin 'lex' (giving us 'legal'), though that comes through a separate line.