Greek-English translations for μηδενικό

• cipher
  a painters cipher, an engravers cipher, etc.
  The message was written in a simple cipher. Anyone could figure it out.
  The message is clearly a cipher, but I cant figure it out.
• zero
  The conductor waited until the passenger count was zero
  A cheque for zero dollars and zero cents crashed the computers on division by zero
  In unary and k-adic notation in general, zero is the empty string