What is the most fundamental meaning of yoga?

The real meaning of yoga is enlightenment.

In detail, yoga is a way of personal practice and enlightenment, with the aim of "integration of body and mind". Yoga terminology is called "Samadhi", which eventually reaches the realm of "Samadhi". The main way is to control and combine body and mind through discipline, asana, breathing, meditation and other methods to achieve a wonderful balance. Of course, if you say it carefully, it should be more than three levels of body and mind, but in general, it should be like this. Different types and factions of yoga are mainly different in methods and approaches, and ultimately they should strive for samadhi. Personally, Samadha (note 1) should be the same as the ultimate realm of Taoist practice and Buddhist meditation. As the saying goes, all roads lead to simplicity, and all roads lead to the same goal.