In Japanese, Mount Fuji is called Fujisan (富士山).
Fujisan has been a sacred site for Shinto and Buddhist worship for centuries. The suffix -san (not to be confused with the personal honorific -san) is used for revered mountains (e.g., Tateyama, Hakusan).
Foreigners often say "Mount Fujiyama," but yama is an alternative reading of san (山). "Fujiyama" is redundant ("Mount Fuji-Mount"). The correct term is Fujisan or, in English, Mount Fuji.
Fujisan remains a powerful national symbol, appearing on the ¥1,000 note, in countless artworks (Hokusai's Thirty-Six Views), and as a UNESCO World Heritage site.