Read this from Wikipedia:

"Flash memory is a later form of EEPROM. In the industry, there is a convention to reserve the term EEPROM to byte-wise writeable memories compared to block-wise writable flash memories. EEPROM takes more die area than flash memory for the same capacity because each cell usually needs both a read, write and erase transistor, while in flash memory the erase circuits are shared by large blocks of cells (often 512×8)..."

For details see http://en.wikipedia.org/wiki/EEPROM and

http://en.wikipedia.org/wiki/Flash_memory

Cheers

ethobil

thanks for your comment

Flash is EEPROM that is erased in single stroke entire memory. EEPROM is byte erase or byte wise rewrite memory.