ĪSHVAR from Sanskrit Īśvara (īśa = ruler, master, lord+vara = environing, enclosing, i.e. the all-pervasive Lord) is one of the several names used in Indian philosophy for God, the Ultimate Reality, also known as Brahman. There is however a subtle conceptual difference between Īśvara and Brahman as interpreted by Śaṅkarāchārya, philosopher of Vedānta. Brahman, he holds, is the Ultimate Reality or Pure Consciousness devoid of all attributes (nirguṇa) and all categories of the intellect (nirviśeṣa), while Īśvara is the personal aspect of the impersonal Brahman. Īśvara is Apara Brahman or Lower Brahman as compared to the Absolute which is called Pāra Brahma or Higher Brahman. Īśvara is the phenomenal aspect of the Transcendent Brahman who is Infinite, beyond the reach of finite thought and who can only be described in negative terms such as ineffable, indescribable, acosmic, timeless, etc. All normal talk about God is therefore about Īśvara. Even positive attributes such as transcendent, self-existent, perfect, etc. really refer to "conditioned Īśvara" rather than to the "unconditioned Brahman". In brief, Īśvara is God as related to the phenomenal reality, the personal aspect of the impersonal Reality. He is the Lord of Māyā, the Creator, Sustainer and Destroyer, immanent throughout His creation.

         In Sanskrit, īśa and īśvara are also defined as name of the Hindu gods Śiva, Kubera and one of the Rudras and even as "name of the goddess Durgā or any other of the Śaktis or female energies of the deities." In Gurū Granth Sāhib, the Sikh Scripture, Īs, Īsar or Īsuru, Punjabi forms of Skt. Īśvara, appear sparingly for Śiva as well as for God (GG, 2, 6, 316, 516, 923, 925, 1082); īsur once stands for great men is general (GG, 816) ; and īsaru once as name of a person other than Śiva (GG, 952) . The composite term paramesar (Skt. parameśvara = parama, supreme, highest + Īśvara) for God appears more often; once it is spelt even paramesvar (GG, 299).

         Sikhism does recognize the traditional categories of transcendent and immanent as also of nirguṇa (without attributes) and saguṇa (with attributes, sarguṇa in Punjabi), pertaining to God, but not the Śaṅkarite distinction between higher and lower Brahman. The emphasis here is on the unicity of Ultimate Reality, the "1 Oṅkār". The term Pārbrahma (Śaṅkara's Pāra Brahman) appears frequently in the Sikh Scripture but Aparbrahma or Apara Brahman never. For the Sikhs the same Absolute is both nirguṇa and sarguṇa (GG, 98, 128, 250, 287, 290, 862). The nirguṇa Brahman manifests himself as sarguṇa Brahman, in relation to His attributes.