Hatha yoga is a generic term that refers to any type of yoga that teaches physical postures. Nearly every type of yoga class taught in the West is Hatha yoga. When a class is marketed as Hatha, it generally means that you will get a gentle introduction to the most basic yoga postures. You probably won't work up a sweat in a hatha yoga class, but you should end up leaving class feeling longer, looser, and more relaxed.