The term "Volunteer navy" can be replaced with several synonyms such as temporary navy, auxiliary navy, reserve navy, or citizen navy. A volunteer navy is a temporary organization composed of non-professional sailors serving on ships that are usually not part of any national navy. The volunteers are mainly used for training purposes, coastal defense, and disaster relief operations. A reserve navy is made up of citizens who received naval training and can be called up in times of war or emergency. An auxiliary navy is a navy made of non-warships, like supply ships or hospital ships, that support a nation's main naval fleet. Citizen navy or people's navy, commonly used in Asian countries, is also another term for a volunteer navy.