#include EEPROM

EEPRPM stands for Electrically Erasable Programmable Read Only Memory.

The EEPROM is a special type of memory where information can be saved and retrieved.  This is NonVolitile Memory which means it does not go away when the power is removed from the Arduino.  This is a good place to store Calibration Data, Password info, High Scores etc.

Note: EEPROM memory have a limited number of WRITEs.  Usually about 1 million.  While this seems like a lot, this can be done by an Arduino in a few seconds.  Make sure you have written your code so the writing is done once as needed.  EEPROM can be read repeatedly without degrading the memory.