Vrat (also spelled Vrata) is a religious vow, typically involving fasting, that Hindus observe for spiritual purification, fulfillment of wishes, or devotion to a specific deity. Vrats range from simple (skipping one meal) to rigorous (complete abstinence from food and water, as in Nirjala Ekadashi). Types include: Nitya Vrat (daily observance), Naimittika Vrat (occasional, tied to specific occasions), and Kamya Vrat (performed for specific desires). Common Vrats include Ekadashi Vrat (twice monthly for Vishnu), Monday Vrat (for Shiva), Thursday Vrat (for Vishnu/Brihaspati), Karva Chauth (for spouse's longevity), Navratri Vrat (nine days for Durga), and Shravan Somvar (Mondays in Shravan for Shiva). Each Vrat has specific rules about what can be eaten, when to break the fast, and which mantras to chant.