What does ember mean from the movie City of Ember?

This is an easy question to answer. Ember is a girl, and a real person until one fatal day.

Ember is sleeping in her room, and her parents are sleeping in their room. Ember's mother got up to go to the bathroom, and she smelled a wired, and strange smell. She ran to her and her husband's room and tells Ember's father and he goes to the kitchen and he saw a fire. The fire was beginning get big. The fire just got bigger and bigger, and bigger. Ember's father cried and Ember's mother cried, and together they escape out of the house. In their hurry, they had left Ember inside the house, in her room, sleeping, all alone with the fire. When she died her mother and father make her a grave and they go to her grave every morning. There was nothing of Ember to save. Ember was very angry at her parents and a few days later she goes to her grave to see them, and they are pray to her and she didn't see they were there. She couldn't be entrusted on her doing, and she was very, very, very angry and she thought to herself to kill them. She goes to her house everyday and made a fire there and when she died she was air and other times she would turn into a fire and when she was fire she remember what had happened on that fateful. She was going to be very angry and she was going to be a ghost with Danny phantom on Nickelodeon.

Note- Whoever wrote this response has bad grammar. You have no idea how much time I spent correcting everything. Everything that person wrote was true, anyway. I also read the series, so I can't criticize that it was wrong, it just had incorrect grammar.