Yoga means union of the individual consciousness or soul with the Universal Consciousness or Spirit.
Yoga - is one of the six major orthodox schools of Hinduism.Ancient, medieval and most modern literature often refers to the Yoga school of Hinduism simply as Yoga. It is closely related to the Samkhya school of Hinduism. The Yoga school's systematic studies to better oneself physically, mentally and spiritually has influenced all other schools of Indian philosophy. The Yoga Sutras of Patanjali is a key of the Yoga school of Hinduism.
The epistemology of the Yoga school of Hinduism, like the Sāmkhya school, relies on three of six Pramanas as the means of gaining reliable knowledge. These include Pratyakṣa (perception), Anumāṇa (inference) and Sabda (Āptavacana, word/testimony of reliable sources). The metaphysics of Yoga is built on the same dualist foundation as the Samkhya school. The universe is conceptualized as composed of two realities in the Samhkya-Yoga schools: Puruṣa (consciousness) and prakriti (matter). Jiva (a living being) is considered as a state in which puruṣa is bonded to prakriti in some form, in various permutations and combinations of various elements, senses, feelings, activity and mind.During the state of imbalance or ignorance, one of more constituents overwhelm the others, creating a form of bondage. The end of this bondage is called liberation, or moksha, by both the Yoga and Samkhya schools of Hinduism.The ethical theory of the Yoga school is based on Yamas and Niyama, as well as elements of the Guṇa theory of Samkhya.
The Yoga school of Hinduism differs from the closely related non-theistic/atheistic Samkhya school by incorporating the concept of a "personal, yet essentially inactive, deity" or "personal god" (Ishvara).While the Samkhya school suggests that jnana (knowledge) is a sufficient means to moksha, the Yoga school suggests that systematic techniques and practice, or personal experimentation, combined with Samkhya's approach to knowledge, is the path to moksha. Yoga shares several central ideas with the Advaita Vedanta school of Hinduism, with the difference that Yoga philosophy is a form of experimental mysticism, while Advaita Vedanta is a form of monistic personalism. Advaita Vedanta, and other schools of Hinduism, accept, adopt and build upon many of the teachings and techniques of Yoga.