萬一

万一
wànyī
  1. just in case
  2. if by any chance
  3. contingency

CEDICT

Entry Composition

1 萬 wàn
  1. ten thousand
  2. a great number
2 一 yī
  1. one
  2. single
  3. a (article)
  4. as soon as
  5. entire; whole; all; throughout
  6. "one" radical in Chinese characters (Kangxi radical 1)
  7. also pr. yāo for greater clarity when spelling out numbers digit by digit