Traditional clay oil lamps used during Diwali are called diyas. A diya is a small lamp, usually made from fired clay, with a cotton wick soaked in vegetable oil or ghee.
Diyas are placed on windowsills, doorways, balconies, temple steps, household boundaries, and sometimes in rows around courtyards. Lighting them is both a practical festive custom and a religious symbol: the flame represents light, knowledge, hope, prosperity, and the triumph of good over evil.
The everyday clay version is especially associated with Diwali, but Indian oil lamps also come in brass, silver, stone, leaf, and other forms. Some metal lamps hold several wicks and are used throughout the year in temples and domestic worship. Regional names include deepam, deepa, divaa, and similar forms.
Diyas are not the same as candles, lanterns, or torches. Candles may also be used in modern celebrations, but “diya” specifically identifies the traditional Indian ritual lamp. The word is closely connected with Deepavali, whose Sanskrit elements refer to a row or series of lights.