Yoga is the ancient Indian practice of balancing mind, body and spirit
In Sanskrit, "yoga" means "the union of self with the truth; joining mind, body and spirit to ultimately sharpen the intuition." In other words, through yoga, you the practitioner can become master of your emotions, thoughts and actions.
Hatha yoga is a practice which follows eight principles, also referred to as Astanga.
Read more about Hatha Yoga.