Definitions for Mythology.

1) A body of myths relating to a particular country or person; the study of myths.
2) A body or collection of myths belonging to a people and addressing their origin, history, deities, ancestors, and heroes; a body of myths associated with an event, individual, or institution; the field of scholarship dealing with the systematic collection and study of myths.
3) Is the "branch of knowledge that deals with myths; the study of myths". In addition, it refers to the body of myths from a particular culture or religion.
4) For our purposes the word mythology has two related meanings. Firstly it refers to a collection of myths that together form a mythological system. Thus one can speak of "Egyptian Mythology", "Indian Mythology", "Maori Mythology" or "Greek Mythology". In this sense one is describing a system of myths which were used by a particular society at some particular time in human history. It is also possible to group mythologies in other ways. For example one can group them geographically and then speak of "Oceanic Mythology", "Oriental Mythology" and "African Mythology".
A second meaning of the term mythology is the academic study of myths and systems of myths in general.

5)
a. A body or collection of myths belonging to a people and addressing their origin, history, deities, ancestors, and heroes.
b. A body of myths associated with an event, individual, or institution: “A new mythology, essential to the . . . American funeral rite, has grown up” (Jessica Mitford)
2. The field of scholarship dealing with the systematic collection and study of myths.

The Purpose of mythology is to explain the believes of differents cultures and their gods. It also show the prespective of different cultures ways of believing in creation of the human race.

In My Own Words

The believe of myths, Gods and Goddess to serve as food for ones soul. The believe of the spirit world. The study of myths.

The purpuse o0f mythology is the way different cultures use gods and goddess to explin their excistence in the world because each culture believes that a god created them.