Hence, whenever there is any mention of yoga, it is usually implied that the person is talking about Jnana Yoga

Gyan means knowledge. This yoga is the yoga of intelligent and selected people. This yoga is the ultimate goal of all other types of yoga. This yoga teaches you to see the world as it is, without any ignorance and prejudice. You can achieve this state by practicing strict mental discipline and virtue. This yoga is also called Rajayoga or the king of all yogas, because it is the most diverse and dominates all other yogas. This is the yoga that Patanjali has described in his Yoga Sutras. This yoga is made up of eight limbs out of which five are external and the remaining three are internal. Its two parts, i.e. Yama and Niyama, relate to the behaviors that a student of Yoga should avoid such as lying, cheating, stealing, etc. and the behaviors that he should practice such as cleanliness, non-hoarding, etc. Asanas and pranayama are the next two parts of this yoga. Asanas are physical activities that help in developing suppleness of the body and thus treating any disease. You can control your breathing by using pranayam which increases the air taking capacity of the lungs and thus increases the vitality of the body. The next part Pratyahara refers to the withdrawal of the senses from the objects of enjoyment. The remaining three parts relate to deep mental concentration. Patanjali said that by practicing these eight limbs of yoga devotedly and intensely, all the impurities of body and mind will be eradicated in time and thus enlightenment will be achieved which will free the person from bondage and ignorance. Because it is made up of eight limbs, this yoga is called Ashtanga Yoga. Because of its emphasis on mental concentration, it is also called Dhyana Yoga. Therefore, whenever yoga is mentioned, it is usually implied that the person is talking about Jnana Yoga.