Nationality law is the law of a sovereign state, and of each of its jurisdictions, that defines the legal manner in which a national identity is acquired and how it may be lost. In international law, the legal means to acquire nationality and formal membership in a nation are separated from the relationship between a national and the nation, known as citizenship. Some nations domestically use the terms interchangeably, though by the 20th century, nationality had commonly come to mean the status of belonging to a particular nation with no regard to the type of governance which established a relationship between the nation and its people. In law, nationality describes the relationship of a national to the state under international law and citizenship describes the relationship of a citizen within the state under domestic statutes. Different regulatory agencies monitor legal compliance for nationality and citizenship. A person in a country of which he or she is not a national is generally regarded by that country as a foreigner or alien. A person who has no recognised nationality to any jurisdiction is regarded as stateless.