It reffers to a kind of MCU which has both a FLASH rom for a code and a EEPROM rom for storing datas at running time.

Rewritable rom type. It is possible to rewrite many times. It is a specific type of EEPROM that is erased and programmed in large blocks. So it's operation is fast. But while MCU is running it is not possible to rewrite the code.

One Time Programmerble. It is not possible to rewrite after write a code. It has been continuoussly replaced with FLASH type.

A rom which is programmed at the manufacturing time. And it is not rewritable. But it is cheaper than other kinds of ROM. So It is common practice to use rewritalbe type rom for the development phase of a project , and to switch to mask ROM when the code has been finalized.