Lightning is a natural phenomenon formed by electrostatic discharges through the atmosphere between two electrically charged regions, either both in the atmosphere or with one in the atmosphere and on the ground, temporarily neutralizing these in a near-instantaneous release of an average of one gigajoule of energy. This discharge may produce a wide range of electromagnetic radiation, from heat created by the rapid movement of electrons, to brilliant flashes of visible light in the form of black-body radiation. Lightning causes thunder, a sound from the shock wave which develops as gases in the vicinity of the discharge experience a sudden increase in pressure. Lightning occurs commonly during thunderstorms as well as other types of energetic weather systems, but volcanic lightning can also occur during volcanic eruptions. Lightning is an atmospheric electrical phenomenon and contributes to the global atmospheric electrical circuit.

तड़ित (Lightning) या "आकाशीय बिजली" वायुमण्डल में विद्युत आवेश का डिस्चार्ज होना और उससे उत्पन्न कड़कड़ाहट (thunder) को तड़ित कहते हैं। संसार में प्रतिवर्ष लगभग 2करोड़ 60 लाख तड़ित पैदा होते हैं।