An NRE account is a bank account opened in India in the name of an NRI, to park his foreign earnings; whereas, an NRO account is a bank account opened in India in the name of an NRI, to manage the income earned by him in India.
FCNR stands for Foreign Currency Non Resident account. This is a kind of fixed deposit account opened for depositing income earned overseas. The account is held in foreign currency.
(Note that interest on NRO account is taxable whereas interest earned on NRE account is exempt from tax. Interest income earned from your FCNR deposit accounts shall be exempt from tax till you hold Non-Resident Indian (NRI) status or Resident and Not Ordinarily Resident (RNOR) status.)
