Yoga means "to unite, to come together, to yoke". This union may take place in the form of a class setting, where a community of people are joining together, or it may be the uniting of one's own mind, body and spirit, or,ideally, a mixture of both.
Yoga itself has many branches, but is most often referred to as the physical practice, also known as asana. Within this practice, a class will often focus on breathwork, strengthening and stretching, holding postures, flowing through postures, balancing, core work and meditation.
There are also many different styles of yoga. There is no right or wrong yoga. Yoga itself is always growing, thriving, sharing and evolving. When you go into a class, expect the unexpected and allow yourself to go on a judgement free journey of mind, body and spirit.