通信

tōngxìn
  1. to correspond (by letter, email etc)
  2. to send or receive messages through telecommunications

CEDICT

Entry Composition

1 通 tōng
  1. to go through
  2. to know well
  3. (suffix) expert
  4. to connect
  5. to communicate
  6. open
  7. to clear
  8. classifier for letters, telegrams, phone calls etc
2 信 xìn
  1. letter
  2. mail
  3. to trust
  4. to believe
  5. to profess faith in
  6. truthful
  7. confidence
  8. trust
  9. at will
  10. at random

classifier: 封