Origin of banzai
- Japanese (may you live) ten thousand years! from Middle Chinese ʋaːn`` syaj` (also the source of Mandarin wànsuì) ʋaːn`` ten thousand syaj` year
From American Heritage Dictionary of the English Language, 5th Edition
- From Japanese 万歳 (ばんざい banzai), from Middle Chinese 萬歲 (mjòn-sjwèi), from Old Chinese 萬歲 (*mans s-qʷʰats "10,000 years [of life]", i.e. "immortality"), from 萬 ("10,000") + 歲 ("Jupiter", "year") (compare Mandarin wànsùi 万岁).