What was the original Japanese name that became “Pokémon”?

The original Japanese name that became “Pokémon” was Pocket Monsters.

Satoshi Tajiri’s project was first known as Capsule Monsters during development, but that name could not be trademarked. The concept was then renamed Pocket Monsters, written as Poketto Monsutā in Japanese. Pokémon is a shortened form of that phrase.

The name reflects the games’ central idea: creatures are stored in compact containers and brought out for adventure and battle. The project’s collecting concept also drew on Tajiri’s childhood interest in catching insects and small animals.

In Japan, the first games were officially titled Pocket Monsters Red and Green. International versions used Pokémon as the global brand name, partly because “Pocket Monsters” was considered difficult to protect and potentially confusing in some markets.