Simple meaning of Yoga is Union.
Ha means Sun and Tha means Moon. Ha-tha Yoga works more on human body. It gives strong and clean body like the diamond if practiced regularly. There are originally only 82 Asanas in Ha-tha Yoga Pradipika written by great saint Gorakh Nath. Asana means body posture which can be attained easily e.g. (i) the Simhasana (lion pose) is useful for alleviating numerous throat, mouth, nose and even ear diseases and give great confidence in life and (ii) the Padmasana (lotus pose), also known as Buddha Posture, gives straight back and lowest effect of gravitation. Many Yogis have practiced this Asana and attained the enlightenment. Now-a-days, many people manipulated and created so many Asanas apart from the original Hatha Yoga Asanas. It is always better to go for original task.
We live in deep illusion of future dreams. We dream not only in night but also in day. Scientist says, we can live without sleep, but we cannot live without dreams. Yoga is a science which can bring one to just now (present) because we remain in past and we think that we are thinking for future also but whatever we think for future, that thought is based on past. Whenever tomorrow comes, it comes as today not as tomorrow. Patanjali is a great name wherever Yoga is concerned. This man is rarest of the rare like Einstein in human history. In Hindu Yoga system, body and mind (Chitta) is a uni-mystical e.g. when we drink alcohol, it goes in body but affects the mind. We also call Patanjali Yoga as the Kriya Yoga which helps the balancing of body and mind. Whenever there is a headache, only then we feel we have the head. It means we live without. Only Kriya Yoga will help come within very fast.