What name did Game Freak originally use for the Pokémon project before adopting Pocket Monsters?

Game Freak originally called the Pokémon project Capsule Monsters.

The early concept reflected the idea that captured creatures could be stored in capsules and released for battles. Satoshi Tajiri’s childhood interest in collecting insects and other small creatures supplied the collecting inspiration, while Japanese monster media influenced the capsule concept.

The name Capsule Monsters could not be trademarked, so the project was renamed Pocket Monsters. In Japan, the title became Poketto Monsutā, commonly written internationally as Pokémon. The accented spelling is a shortened form of the romanized Japanese name.

The name change happened during development rather than after the games became famous. This history is easy to miss because the final name appears on the original releases, while Capsule Monsters survives mainly in accounts of the project’s early design stage.