tavanlaillisen

Tavanlaillinen is a Finnish adjective used in juridical and historical contexts to describe something governed by customary law or based on long-standing practice rather than written statutory law. The term combines tavan, meaning habit or custom, with laillinen, meaning legal, to denote law that arises from customary practice rather than formal statutes.

In usage, tavanlaillinen typically appears in phrases such as tavanlaillisen oikeuden mukaan or tavanlaillisen oikeuden perusteella, meaning “according to customary law” or “on the basis of customary law.” Grammatically, the form tavanlaillisen is the genitive singular, while related forms include tavanlaillinen (nominative) and tavanlaillista (partitive). The concept is mostly encountered in legal history, doctrinal writings, and discussions comparing customary practices with codified law.

Relation to other terms: tavanlaillinen is distinct from tavanomainen, which means customary or ordinary in a general sense, and from laillinen, which means lawful or legal in a statutory sense. While modern Finnish law is predominantly codified, customary law may still be referenced in historical analyses or in comparative contexts where long-standing practices influence private law or community norms.

See also: customary law, Finnish legal terminology, legal history. In contemporary Finnish jurisprudence, the notion of tavanlaillinen serves mainly a descriptive and historical role, rather than as a primary source of binding rules.