A clear definition of yoga:

A life that is balanced, free from extremes, recognising oneself as a spiritual person, taking guidance from Gita and Teacher who has assimilated and followed the disciplines or at least is in the process of assimilating and totally committed to a life of dharma, universal values and truth.
Emphasizing knowledge of oneself, the world and God, and understanding what is the purpose of life and the common human goal. One meaning in Sanskrit is ‘upayah’ – a means to reach an end, the end being emotional maturity, objectivity. The means are given in the Bhagavad Gita – Value of Values, Yama Niyama, disciplines of Asanas and 5 daily sacrifices are all included in the meaning and need to be discovered by the student.
Every being is searching balance and harmony in life. Yoga provides the practices and disciplines as well as the knowledge to help us find that peace in all aspects of life. As well as understanding the choices that bring us equanimity.
When the teaching is understood properly and the disciplines are practiced one will be able live from the heart, stay in relaxation, trust and contentment with whatever one’s life brings.
The Bhagavad Gita states:
‘Being firm in the attitude of glad acceptance towards all the results, having given up the attachment to the results of our actions and being objective towards success and failure in life, is said to be yoga.’