The collection, yoga, the word defined. These are some of the western translations and definitions that have influenced many of the opinions of those who have or have not practiced yoga.

• Encyclopaedia Britanica 1910
  YOGA, diversion of the senses from the external world, and concentration of thought within (Sanskrit yoking.) The Yoga system in HIndu philosophy is a branch of the Sankhya (q.v.), but loosely inserted into it is the conception of a personal God, who is indissolubly connected with the subtlest form of matter. Union with him was not the original object of yoga. By its practices of hypnotism and self-mortification the Yogi (mod. Jogi) could attain miraculous powers and control of nature itself. Siva (q.v.), was essentially the great Yogi.
• Man's Eternal Quest by Paramahansa Yogananda 1925
  Yoga. From Sanskrit yui, union. The highest connotation of the word yoga in Hindu philosophy is union of the individual soul with Spirit through scientific methods of meditation. Within the larger spectrum of Hindu philosophy, Yoga is one of six orthodox systems: Vendanta, Mimamsa, Sankhya, Vaisesika, Nyaya, and Yoga. There are also various types of yoga methods: Hatha Yoga, Mantra Yoga, Laya Yoga, Karma Yoga, Jnana Yoga, Bhakti Yoga, and Raja Yoga.
• The Yoga of the Bhagavat Gita by Sri Krishna Prem 1938
  Yoga: Union, joining. The Path on which the self is united to the Self and the Self to the All.
• Transformations of Myth Though Time by Joseph Campbell 1904-1987
  The idea of yoga is already given in the name, yoga. It comes from the root yuj, which means (to yoke), to connect or join something to something else, What is being yoked is our ego consciousness, the aham consciousness, to the source of consciousness.
• How To Know God The Yoga Aphorisms of Pantanjali Translated by Swami Prabhavananda and Christopher Isherwood 1946
  Yoga cannot be neatly defined within the boundaries of traditional Western catchwords. Yoga is itself, and as such must be studied before we can understand its nature, its meaning, and its value.
• Funk and Wagnalls Standard Dictionary 1950
  Literally, union: a Hindu system of mystical and ascetic philosophy which involves withdrawal from the world and abstract meditation upon any object, as the Supreme Spirit, ( Brahman),with the purpose of identifing ones self with the object, thus achieving nirvana, and of relieving the soul of the five errors of mind (error, knowledge, imagination, memory, and sleep). The date of the beginning of yoga has never been determined. The doctrine, however, was given its form by Patanjali, author of the Yogasutras, according to which yoga consists of a series of stages which are traversed by means of asana or various bodily attitudes, by holding the breath, and by concentration of the gaze on a particular point.Yoga can gain for a man the power of becoming invisible, of such size as to be able to touch the moon, or of being transported anywhere. By yoga a man can know the past and the future and talk to the dead. By inducing a hypnotic sleep, some yogis (practitioners of yoga) can be buried alive for periods of time without suffering injury.
  The forms of yoga include Hatha yoga in which mastery of the body is obtained by restraining the senses, Bhakti yoga in which devotion to a personal god is the means to mastery of self, Raja yoga which employs mental concentration, and, the highest form, Jnana yoga in which union with the Supreme Spirit is obtained through concentration of the soul upon itself.
• Webster's New Practical School Dictionary 1967
  Yoga (1) A system of mental self-disipline, practiced especially by followers of the Hindu religion, in which the attention is directed solely upon some object, which may be but is not necessarily the deity, with a view to the identification of consciousness with the object. (2) Any set of physical exercises and postures that constitute or are believed to constitute the proper preparatory steps to mental yoga.
• Integral Yoga Hatha by Sri Swami Satchidananda 1970
  Yoga is a scientific system for purifying the body and the mind, for making each of us the master of our senses so that we may develop our emotions and intellect to a level at which we function healthfully and in perfect harmony.
• Get in Touch with Yourself Through Yoga by Tille Mia 1972
  The discipline of Yoga frees the mind from distracting thoughts and teaches it to concentrate on the moment that is now.
• The World Book Encyclopedia 1984
  Yoga is a term that has two meanings. It is both (1) a school of thought in the Hindu religion and (2) a system of mental and physical exercise developed by that school. Followers of the yoga school, who are called yogis or yogins, use yoga exercise to achieve their goal of isolation of the soul from the body and the mind. Many non-Hindus in the Western countries practice some form of yoga exercise in hope of improving their health and achieving peace of mind. The word yoga means discipline in Sanskrit, the classical language of India.
• The Science of Kriya Yoga by Roy Eugene Davis 1985
  Yoga - To yoke, or join together. The system of various compatible disciplines which enable one to harmonize conflicting and active currents in the system so that the light of the soul can be directly experienced.
• Traditional Definitions of Yoga Translated from the Sanskrit by Georg Feuerstein, Ph.D.