Kaiju is a Japanese word that is commonly associated with giant monsters/creatures. A subgenre of science fiction.
From Tarantula (1955) to Mothra (1961), and from recent releases like Pacific Rim (2013) to Dragon Wars (2007), Kaiju movies have been a cinema staple over the years. However, it's widely acknowledged that Godzilla and King Kong are the most globally recognised Kaijus.