What name was used for the Pokémon franchise before its international branding?

The Pokémon franchise was originally called Pocket Monsters.

The Japanese title is Poketto Monsutā, commonly rendered in English as Pocket Monsters. The original Japanese games were titled Pocket Monsters Red and Green, and the franchise’s Japanese name remains Pokémon in romanized form.

The shorter international name Pokémon comes from the Japanese title. The accent mark distinguishes the pronunciation and helps separate the brand from the ordinary English phrase “pocket monsters.”

Players sometimes assume that Pokémon was always the franchise’s worldwide title. In fact, the international name was chosen for branding and trademark reasons, while the original games and early Japanese materials used Pocket Monsters. The familiar shortened form is now used globally.