一切 (yīqiè) is a pronoun meaning 'everything / all', referring to a whole set as a single unit. It often appears with 都 (dōu) for emphasis. Unlike 每 (měi), which highlights each individual member, 一切 treats the group as a whole; unlike 任何 (rènhé), which means 'any' (an arbitrary one), 一切 covers the entire collection without exception.