Diwali (or Deepawali) is the biggest and the brightest of all Hindu festivals celebrated by families around the world. It's the festival of lights which literally illumines the country with its brilliance, brightness and dazzles all with its joy
Diwali comes from the Sanskrit word Deepavali which literally means "a row of lights." This auspicious day, known as the "festival of lights," is celebrated by Hindus around the world. It historically symbolizes the victory of good over evil and celebrates light and life on both community and personal levels.
According to Wikipedia,
While Diwali is popularly known as the "festival of lights", the most significant spiritual meaning is "the awareness of the inner light". The celebration of Diwali as the "victory of good over evil", refers to the light of higher knowledge dispelling all ignorance, the ignorance that masks one's true nature, not as the body, but as the unchanging, infinite, immanent and transcendent reality. With this awakening comes compassion and the awareness of the oneness of all things (higher knowledge). Just as we celebrate the birth of our physical being, Diwali is the celebration of this Inner Light.