In Indian religions, (Sanskrit: सिद्धि ; fulfillment, accomplishment) are material, paranormal, supernatural, or otherwise magical powers, abilities, and attainments that are the products of yogic advancement through sādhanās such as meditation and yoga. The term ṛddhi (Pali: iddhi, "psychic powers") is often used interchangeably in Buddhism.
Siddhi is a Sanskrit noun which can be translated as "knowledge", "accomplishment", "attainment", or "success".
The Visuddhimagga is one of the texts to give explicit details about how spiritual masters were thought to actually manifest supernormal abilities. It states that abilities such as flying through the air, walking through solid obstructions, diving into the ground, walking on water and so forth are achieved through changing one element, such as earth, into another element, such as air. The individual must master kasina meditation before this is possible. Dipa Ma, who trained via the Visuddhimagga, was said to demonstrate these abilities.
In the Panchatantra, an ancient Indian collection of moral fables, siddhi may be the term for any unusual skill or faculty or capability.
In Patañjali's Yoga Sutras IV.1 it is stated, Janma auṣadhi mantra tapaḥ samādhijāḥ siddhayaḥ, "Accomplishments may be attained through birth, the use of herbs, incantations, self-discipline or samadhi".
According to different sources, below are the eight classical siddhis (Ashta Siddhi) or eight great perfections:
Aṇimā: the ability to reduce one's body to the size of an atom.
Mahimā: the ability to expand one's body to an infinitely large size.
Laghimā: the ability to become weightless or lighter than air.
Garimā: the ability to become heavy or dense
Prāpti: the ability to realize whatever one desires.
Prākāmya:the ability to access any place in the world.
Īśiṭva:the ability to control all material elements or natural forces.
Vaśiṭva: the ability to force influence upon anyone.
In Shaivism, siddhis are defined as "Extraordinary powers of the soul, developed through consistent meditation and often uncomfortable and grueling tapas, or awakened naturally through spiritual maturity and yogic sādhanā.