The phoenix is a symbol for renewal, for life that follows death in a cleansing fire. After the city is reduced to ashes by bombers in Fahrenheit 451, Granger makes a direct comparison between human beings and the story of the phoenix.
Another example of symbolism in Fahrenheit 451 would be The Hearth and the Salamander. This is the title of the first section in the book. A hearth is traditionally the center of a house and the source of warmth. The salamander is a symbol of the firemen, and the name they give to their trucks.
