A kaiju is a term used in Japanese popular culture to refer to a genre of giant monsters or creatures, typically depicted in films, television series, and literature. These colossal beings are often portrayed as immense, powerful entities that wreak havoc upon cities and landscapes.

The term "kaiju" consists of two characters:

Kai (怪): This character can be translated as "strange" or "mysterious." It is often used to convey a sense of mystery or awe. In the context of kaiju, it emphasizes the otherworldly and often fantastical nature of these creatures.

Ju (獣): This character translates to "beast" or "creature." It refers to animals or living beings in a general sense.

Combining these two characters, "kaiju" essentially means "strange creature" or "monster" in Japanese. The term has become widely associated with the genre of Japanese science fiction and fantasy that features giant monsters, with Godzilla being one of the most iconic examples. Over time, the concept of kaiju has expanded beyond Japan and is now recognized internationally, particularly in discussions related to giant monsters in various forms of entertainment and popular culture.

Kaiju are characterized by their enormous size, often dwarfing buildings and other structures. They can take various forms, ranging from massive reptilian creatures to robotic behemoths. Godzilla, one of the most iconic kaiju, exemplifies this genre. Godzilla, also known as "Gojira," is a colossal, prehistoric sea monster that has become a symbol of Japanese cinema.

Originally, the word "otaku" (お宅) in Japanese means "your house" or "your home." It is a polite and formal way to address someone else's residence.

The term's shift in meaning and adoption into popular culture occurred in the 1980s. In this context, "otaku" came to refer to a person with an obsessive interest in a particular hobby, often related to anime, manga, video games, or other aspects of Japanese pop culture. These individuals were particularly passionate and knowledgeable about their chosen hobbies, often to the point of being socially withdrawn. Over time, its usage has evolved, and it is now commonly associated with individuals who have a deep interest in anime, manga, and related subcultures.

The modern usage of "otaku" to describe fans of anime and manga gained popularity in the 1980s and 1990s, both in Japan and internationally. It was initially a self-adopted term within the subculture but has since become widely recognized.