This word is used in several senses. When derived from the root ‘yuj samādhau’ it means perfect concentration of mind. If derived from another root, ‘yujir yoge’, it means ‘to unite’. Combining these two senses one can say that it stands for that art and science of concentration of mind which helps the spiritual aspirant to ultimately unite his individual soul (jīvātman) with the Supreme Soul (Paramātman).
The Yogadarśana of Patañjali (200 B. C.) fits in with this description. See YOGADARŚANA for details.
However, in general, this word is often loosely used for any spiritual discipline. A few of them are listed below, arranged in the alphabetical order:
The Taittirīya Upaniṣad (2.1) describes the evolution of the world from the Ātman (same as Brahman), through the five elements like the ākāśa (space, ether) right up to puruṣa (human being). In Abhāvayoga, the aspirant has to meditate on the reverse process, merging each succeeding product in the preceding one, finally arriving at the Ātman-principle which is nirguṇa (without attributes) and nirākāra (without forms) and is pure consciousness. In this state of yoga, the whole world appearance has disappeared (abhāva = nothingness) and only the Ātman is experienced.
This is the yoga in which the mind is prevented from rising in the form of vṛttis (waves) and made absolutely still, whereby the Ātman is experienced. Certain disciplines of Haṭhayoga like the khecarīmudrā (See KHECARĪMUDRĀ.) have to be practised first.
The Yogadarśana of Patañjali (200 B. C.) is named Aṣṭāṅgayoga since it consists of eight limbs (aṣṭa = eight; aṅga = limb or steps). See YOGADARŚANA for details.
After practising mantrajapa (repetition of the divine name) coupled with prāṇāyāma (control of breath) for quite some time, if the japa is given up, leading to the direct experience of the divine presence, it is Bhāvayoga.
The yoga by which the kuṇḍalinī power is taken up through the six cakras right up to the seventh, is called Kuṇḍalinīyoga.
This is another name for Kuṇḍalinī-yoga.
This is the stage next to Abhāvayoga wherein the aspirant will experience his oneness with Śiva or God.
Brahman is all-pervading pure consciousness. When he wills to create the world (vide Chāndogya Upaniṣad 6.2.1 and 3; Taittirīya Upaniṣad 2.6; Aitareya Upaniṣad 1.1) a spanda or nāda (vibration or sound) appears in him. This will gradually evolve into this multiplicity of the universe. That nāda is represented by Praṇava or Oṁ. Meditation on this nāda ultimately leading to the dissolution of the mind and arising of supreme know-ledge is called Nādayoga.
This is the same as the yoga taught by Patañjali (200 B. C.). See YOGADARŚANA for details.
Achieving the unity of the jīvātman (the individual soul) with Paramātman is Śivayoga according to the scriptures of Śaivism. It has five steps: arcana (worship of the chosen deity); anusandhāna (meditating on the form of the deity); bhakti (cultivation of devotion); vidyā (receiving the mantra); vrata (strictly following the disciplines imposed by the guru and the scriptures).
When Mantrayoga is practised along with prāṇāyāma, it is called Sparśayoga.
The path of spiritual discipline described in the works on tantras consisting of ṣaṭcakrabheda (piercing the six cakras) is called Tantrayoga.
(See CAKRAS for details.)
Just as one burning lamp can light another, a perfect guru (spiritual master) can pass on his spiritual power to a qualified or worthy disciple even by a touch. This is called Tārakayoga. It is also called śaktipāta or bequeathing spiritual power.
In Hindu astrology, the word yoga is used in a technical sense to indicate the fourth limb of the pañcāṅga or almanac. (See PAÑCĀṄGA.)