Foreign law refers to the national law (also known as internal or domestic law) of another country.
For example, from the viewpoint of Canada, the laws of Japan, the United Kingdom, and Brazil are all "foreign law". A related concept is comparative law, which refers to the academic study of different jurisdictions' legal systems.
For guidance on starting your research into the laws of other jurisdictions, please see the Foreign Law chapter of the Law Library's Canadian Legal Research Manual.