Navarathri means nine nights. Darkness is associated with night. What is this darkness? It is the darkness of ignorance. The purpose of the Navarathri celebration is to enable man to get rid of the nine types of darkness which have taken hold of him. When a reference is made to Devi, it signifies the unified form of Durga, Lakshmi and Saraswathi. The three together represent Shakthi. Shakthi is the energy that accounts for all the phenomena of Prakruthi (Nature). Nature is energy and the controller of that energy is the Lord.
The Navarathri has been divided into three parts the first three days being dedicated to the worship ofDurga, the next three days to the worship of Lakshmi and the last three days to the worship of Saraswathi.
Outwardly Navarathri signifies truimph of good over evil.Dussera can also be interpreted as “Dasa-Hara”, which means the cutting of the ten heads of Ravana. So,it`s a resolve to cut the ten heads–passion, pride, anger, greed, infatuation, lust, hatred, jealousy, selfishness and crookedness–of the demon, Ego, and thus justify the celebration of Dussera.