ELI5: Explain Like I'm 5

Mobile equipment identifier

A mobile equipment identifier (MEID) is a number that helps identify a specific mobile device. It's like a serial number for a phone so that the phone company can keep track of the device and who it belongs to. MEIDs are used for both cell phones and tablets. They belong to the device, not to the person using it, so if you switch to a different device the MEID will stay the same.