Black’s Law Dictionary defines “customary law” as law “consisting of customs that are accepted as legal requirements or obligatory rules of conduct;  practices and beliefs that are so vital and intrinsic a part of a social and economic system that they are treated as if they were laws.”  Customary law has also been defined as “locally recognized principles, and more specific norms or rules, which are orally held and transmitted, and applied by community institutions to internally govern or guide all aspects of life.”  The ways in which customary laws are embodied differ from one another.  For instance, the laws can be codified, written or oral, expressly articulated or implemented in traditional practices.  Another important element is whether these laws are actually “formally” recognized by and/or linked to the national legal systems of the country in which a community resides.  A decisive factor in determining whether certain customs have status as law is whether they have been and are being viewed by the community as having binding effect, or whether they simply describe actual practices.

Customary laws concern many aspects of communities’ lives.  They define rights and responsibilities of community members on important aspects of their life, culture and world view: customary law can relate to use of and access to natural resources, rights and obligations relating to land, inheritance and property, conduct of spiritual life, maintenance of cultural heritage and knowledge systems, and many other matters. It has been argued that customary law consists of indigenous customs practiced by traditional communities, and carrying along with them local sanctions for their breach.  Most of customary law rules are unwritten and not uniform across ethnic groups.  Differences in the customary laws of ethnic groups can be traced to various factors such as language, proximity, origin, history, social structure and economy.  Customary law is not static, but dynamic; its rules change from time to time to reflect changing social and economic conditions.

Some of the working documents of the IGC make reference to customary laws and protocols and some note that these should be taken into account in devising a new system of protection for traditional knowledge or traditional cultural expressions.