不止(bù zhǐ) - more than, not just in Mandarin

不止 (bù zhǐ) puts a floor under a number rather than a ceiling. 不止一百个 means the true figure passed a hundred and kept going, and 不止一次 is the standard way of saying more than once. The image in the characters is exact: the counting does not stop there.

It also works without a number, in the sense of not merely. 这不止是钱的问题 says the money is real but it is not the whole story. Here it behaves much like 不仅, and the two are often interchangeable in that use.

The trap is the near-identical 不只 (bù zhǐ), which sounds the same and means not only. In careful writing 不止 covers quantity exceeded while 不只 covers the not only, also pattern with 而且. Plenty of native writers blur them, but an exam will not, so keep 不止 for the counting sense. Note too that the first tone shifts: 不 is bù before the third-tone 止.