What was Pokémon originally called in Japan?

Pokémon was originally called Pocket Monsters in Japan.

The Japanese title is Poketto Monsutā, written as ポケットモンスター. It describes the central idea of carrying collectible creatures in portable devices and was shortened to Pokémon for international branding. The accented é helps distinguish the title’s pronunciation and spelling outside Japan.

The name also appears in the Japanese titles of the first games and the original television series. In English-speaking markets, the shorter Pokémon name was easier to use on packaging, television listings, merchandise, and advertising.

The term Pokémon is therefore not the name of a separate later franchise. It is the internationally standardized abbreviation of Pocket Monsters. The shortened form became especially useful as the series expanded into games, cards, animation, films, books, toys, and mobile applications.