孔方兄

kǒngfāngxiōng
(coll., humorous) money (so named because in former times, Chinese coins had a square hole in the middle)

CEDICT

colloquial humorous

Entry Composition

1 孔 kǒng
  1. hole
  2. classifier for cave dwellings

classifier: 個
2 方 fāng
  1. square
  2. power or involution (math.)
  3. upright
  4. honest
  5. fair and square
  6. direction
  7. side
  8. party (to a contract, dispute etc)
  9. place
  10. method
  11. prescription (medicine)
  12. just when
  13. only or just
  14. classifier for square things
  15. abbr. for square or cubic meter
3 兄 xiōng elder brother