Diwali (দেওয়ালী) or Deepavali (দীপাবলী) - popularly
known as the "FESTIVAL OF LIGHTS".
This five day festival starts on Dhanteras and ends on Bhatri Dwitya (ভাই ফোঁটা) [Source: Wikipedia].
The festival of lights (deep = light and avali
= a row i.e., a row of lights), which
literally illumines the country with its brilliance and dazzles all with its
joy, is the celebration of life, its
enjoyment and goodness. According to About.com.Hinduism,this four-day-festival starts after the day of Dhanteras: