Common public thinks that Yoga means practice of Asanas. Virtually asana is the third component part of Aslitanga Yoga. There arc eight component parts of Yoga. The first is Yama. Yamas are five in number i.e., Ahimsa, Satya. Asteya, Brahmacharya and Aparigraha. In Yamas, emphasis is laid to the purification of social life with a view to make it Sattvic and divine. Ahimsa means harmlessness towards all living beings. Satya means truthfulness Asteya means absence of steal or dishonesty. Brahmacharyameans celibacy or purity in sexual life. Aparigraha means-net to posses beyond actual needs. These should be followed by all the practitioners in mind, speech and action.
The second component part of Yoga is Niyama. Niyamas are five in number i.e., Saucha, Santosh, Tapah, Svadhyaya and Ishwarapranidhana. Niyamas aim at acquiring maximum purity, divinity and uprightness in the mind. First is Saucha (external and internal purification). Second is Santosh (contentment). Third is Tapah (to make incessant righteous efforts to achieve goal in the teeth of all adversities and obstructions. Fourth is Svadhyaya (to study spiritual scriptures to acquire correct knowledge of self and the Supreme Divinity) and the fifth is Ishwarapranidhana (complete surrender to the divine will).
The third component part of Yoga is Asana. Usually, we all are very well known to it. The constant uninterrupted and pleasurely sitting is called Asana. Its practice removes the unsteadiness of body, unstability, dizziness and Pramad etc. and develops strength, glow, elasticity, lightness, smartness, positive health and capacity of tolerating heat and cold, hunger and thirst and tiredness etc. The asanas are practised to energise the body and mind with the requisite vitality and vigour to successfully follow the higher practices of meditation.
The fourth component part of Yoga is Pranayama. Due to its practice man gets encouragement and vital power, control of Prana, concentration of mind and ability to perform the higher practices of Yoga i.e., Dharana, Dhyana and Samadhi.
The fifth component part of Yoga is Pratyahara. In the practice of Pratyahara all the senses renounce their objects and get internalised. By the practice of Pratyahara, Yogis acquire perfect control over their senses.
The sixth component part of Yoga is Dharana. In this practice, the mind is to be concentrated over one object by restraining it from external subjects. Usually we find ourselves unable to concentrate our mind on an object even by making conscious efforts for the same. With constant practice our concentration power is increased to such an extent that we can concentrate our mind fully over any object at will and the mind do not entertain any other subject except that subject.
The seventh component part of Yoga is Dhyana. We are well acquainted with this word but very few people possess its correct understanding. By the practice of Dhyana Mind can be fixed upon any object even for long hours. In the process of Dharana Mind does not concentrate over an object uninterruptedly due to external or internal obstructions. In Dhyana it continues constantly. Dhyana is the higher and mature stage of Dharana. In Samkhya philosophy the state of Dhyana is defined as Nirvisayam i.e. devoid of any object means restrained from all external and internal objects and is constantly and uninterruptedly fixed upon the object of Meditation this state is called Dhyana.
The eight component part of Yoga is Samadhi. After full maturity Dhyana is called as Samadhi. Samadhi is also described in many ways.
The first five component parts of Yoga i.e., Yama, Niyama, Asana, Pranayama and Pratyahara are called Bahiranga Yoga which means external or lower Yoga and Dharana, Dhyana, Samadhi are called Antaranga Yoga - which means internal or higher Yoga.