Kaiju is a Japanese word meaning "strange creature". In English, it has come to mean "monster" or "giant monster", referring to creatures of a large size seen in movies from Asia. Many kaiju movies are made in Japan. It is a type of tokusatsu entertainment. Kaiju movies usually show a monster attacking a major Japanese city or battling other monsters.
Terms that are related to kaiju include kaijū eiga, movies with several large monsters or a single monster, kaijin, movies with a human-like monster, and daikaiju, movies with very large monsters.