Origins
The word 'law' has a surprisingly physical etymology: it means 'something laid down,' evoking the image of rules placed in position like stones in a wall or layers in a foundation. It comes from Old English 'lagu' (law, ordinance), borrowed from Old Norse 'lǫg' (law, things laid down), the plural of 'lag' (a layer, something laid), from Proto-Germanic *lagą (that which is laid, a layer), from PIE *legʰ- (to lie down, to lay).
The Norse origin of the English word 'law' is itself historically significant. Old English had its own legal vocabulary — 'dōm' (judgment, decree — surviving in 'doom'), 'riht' (right), and 'ǣ' (law, custom) — but the Norse 'lagu/lǫg' displaced these native terms during the period of Scandinavian settlement in England (9th–11th centuries). The Danelaw — the area of England under Norse legal jurisdiction — was literally 'Dane-law,' and the Norse word for law became the standard English term. English legal vocabulary is thus partly a legacy of Viking colonization.
The PIE root *legʰ- (to lie, to lay) produced a coherent family of English words. 'Lay' (to put something down) is a native Germanic verb from the same root. 'Layer' (something laid flat). 'Lair' (a lying-down place, a den — originally any bed or resting place). 'Ledger' (something laid out for recording accounts). 'Lager' (beer that is 'laid down' to mature, from German 'Lagerbier,' stored beer). 'Byelaw' (from Old Norse 'bý-lǫg,' town-law — the laws of a local community).
Old English Period
The compound 'outlaw' (from Old Norse 'útlagi') meant not simply 'a criminal' but something more specific and severe: a person formally placed outside the protection of the law. An outlaw had no legal rights — they could be killed, robbed, or harmed with impunity, because the law no longer 'lay over' them. Outlawry was one of the most feared punishments in Norse and Anglo-Saxon society, amounting to civil death.
The metaphor of law as 'something laid down' is conceptually distinct from other European legal etymologies. Latin 'lēx' (law, from 'legere,' to read or to choose) frames law as something read or selected. German 'Gesetz' (law, from 'setzen,' to set, to place) is closer to the Norse metaphor — law as something set in position. Greek 'nómos' (law, from 'némein,' to distribute) frames law as something apportioned. Each etymology reveals a different civilization's understanding of what law fundamentally is.