1. A human or animal corpse that has been embalmed and wrapped in linen bandages: The mummy in the story Mary was reading was to be buried like it used to be done by ancient Egyptians and by some Native American tribes.

A mummy can also be a naturally preserved human or animal body.
2. A substance that was used in medicine: Mummy used to be prepared from mummified flesh.
3. A reanimated corpse in a horror film: There was a really scary movie on TV where a corpse was reanimated as a woman after being embalmed and the mummy roamed the streets of the city at night.