The word yoga has a wide range of applications in the Sanskrit language, from "union," to "team," to "sum," etc. Early on, it came to be applied also to spiritual endeavor, specifically the control of the mind and senses. This usage is first found in the second millennium BCE. By the third or fourth century BCE, the word yoga was widely used to denote the Hindu tradition of spiritual discipline, comprising different approaches to Self-realization, or enlightenment. (Shambhala Encyclopedia of Yoga by Georg Feuerstein).
Now, in 2019, yoga in North America is widely understood as referring to "Hatha Yoga", loosely described as the vast body of doctrines and practices geared toward self-realization by means of perfecting the body. Its interpretation has become even more narrowly translated though to mean "postures and breathing". It is important to note that Hatha Yoga is only one of dozens of yoga practices some of which include Bhakti-Yoga, Jnana-Yoga, Karma-Yoga.
This point is not meant to negate our enthusiasm and interest in the very practical benefits of yoga (increasing concentration, improving flexibility, improving breathing etc.). To the contrary, it is to highlight for those interested or ready, that yoga (as does similar disciplines) has the capacity to take us much more deeply into ourselves and I believe to a place of wisdom where the keys to peace and tolerance in the world reside.
We search far and wide for knowledge outside of ourselves and in this information age it is quite apparent that this search is endless. We yearn to understand our world as it is a fascinating place. I offer that with patience and discipline we can find that our internal landscape is as full of intrigue and excitement as our external one.