The story
- Old Norse · derived frombýjar“town's; settlement's”
- Middle English · inherited frombyrelawe
- Old English · inherited frombīlage“bylaw”
- Middle English · inherited frombylawe
- English todaybylaw
From Middle English bylawe, bilawe, partly from Old English bīlage (“bylaw”) and partly from a variant of Middle English byrelawe, birlawe, from Old Norse býjar (“town's; settlement's”) + lǫg (“laws; jurisdiction”). Byrlaw is attested earlier in English but is unattested in Old Norse and the cognates in Scandinavian languages follow the development of bylaw: Danish bylov (“municipal law”), Swedish bylag and byalag.
Etymology from Wiktionary, CC BY-SA 4.0.