Definition
Brahman is the Absolute Reality in Hindu philosophy — the infinite, eternal, formless, all-pervading ground of all existence. It is described as Sat-Chit-Ananda (Existence-Consciousness-Bliss). Brahman is not a personal God but the impersonal Absolute — though it can be worshipped through personal forms (saguna Brahman / Ishvara). "Sarvam khalvidam brahma" — "All this is verily Brahman" (Chandogya Upanishad). Brahman is beyond all attributes (nirguna) and descriptions — "neti neti" (not this, not this). Yet it is the source and substance of everything. The realization of Brahman is the highest goal of the Vedanta philosophy. In Advaita, the individual Self (Ātman) is identical with Brahman. In Vishishtadvaita, the world and souls are the body of Brahman. In Dvaita, Brahman (God) is eternally distinct from souls.
Etymology
From the root brh (बृह्), "to grow, expand, be great." Brahman is "the expanding one" — that which is infinitely great, all-pervading. Originally referred to the sacred power of the Vedic mantra and the priest who wields it (brahmin), then evolved to mean the ultimate Reality.
Key Texts
Related Verses
सर्वं खल्विदं ब्रह्म
sarvaṃ khalvidaṃ brahma
All this is verily Brahman. Everything emerges from, is sustained by, and dissolves into Brahman.
Chandogya Upanishad 3.14.1सत्यं ज्ञानमनन्तं ब्रह्म
satyaṃ jñānamanantaṃ brahma
Brahman is Truth, Knowledge, and Infinite — this is the definition of the Absolute.
Taittiriya Upanishad 2.1.1नेति नेति
neti neti
Not this, not this — Brahman cannot be described by any positive attribute. It is beyond all conceptualization.
Brihadaranyaka Upanishad 3.9.26परमं ब्रह्म परमं धाम पवित्रं परमं भवान्
paraṃ brahma paraṃ dhāma pavitraṃ paraṃ bhavān
You are the Supreme Brahman, the supreme abode, the supreme purifier.
Bhagavad Gita 10.12Interpretations Across Traditions
Advaita Vedanta
Brahman is the only reality. The world is maya (appearance). "Brahma satyam jaganmithya" — Brahman is real, the world is appearance. The Self is Brahman.
Vishishtadvaita (Ramanuja)
Brahman is the supreme reality with attributes (saguna). The world and souls are real as the body of Brahman. Brahman is Narayana (Vishnu).
Dvaita (Madhva)
Brahman is the supreme God (Vishnu), eternally distinct from matter and souls. Brahman is personal and endowed with infinite auspicious attributes.
Achintya Bhedabheda (Chaitanya)
Brahman is Krishna — simultaneously one with and different from the world and souls. Inconceivable simultaneous oneness and difference.