Himitsu

Himitsu is the romanization of the Japanese noun 秘密, meaning "secret" or "privacy." It denotes information that is intended to be concealed or not disclosed. The characters 秘 (hi) and 密 (mitsu) together express the idea of hidden or confidential knowledge. In ordinary Japanese, himitsu appears in phrases describing confidential matters or private information, such as 秘密を守る (to keep a secret), 秘密を打ち明ける (to reveal a secret), 秘密基地 (secret base), or 秘密裏に (in secret). It functions as a common noun and appears in both formal and informal speech.

In popular culture, himitsu is frequently used as a title or motif for works that center on secrecy, espionage, romance, or mystery. In English-language catalogs, such works are typically translated as "Secret." Because of its ubiquity, "Himitsu" or its English equivalent appears in many Japanese films, manga, music, and novels, sometimes as an official title and sometimes as a thematic element within a work. The term can function as a proper title or as a keyword that signals a central theme of confidentiality or undisclosed information.

The concept of secrecy in Japanese literature and media often explores themes of privacy, trust, and disclosure, sometimes intersecting with social expectations around harmony and face. As a word and as a title component, himitsu is recognized by speakers of Japanese and is sometimes used in non-Japanese contexts to evoke mystery or intrigue.