Hatha yoga can be described as ‘Hatha’ will typically involve a set of physical postures (yoga poses) and breathing techniques. These are typically practiced more slowly and with more static posture holds than a Vinyasa flow or Ashtanga class. Literally however, Hatha means ‘force’ and is more traditionally defined as ‘the yoga of force’, or ‘the means of attaining a state of yoga through force’. So Hatha yoga can be considered as anything you might do with the body, including:

asana – yoga postures (practised in any style of ‘yoga’)
pranayama – breathing techniques
mantra – chanting or reciting
mudra – hand gestures
shatkriyas and shatkarmas – cleansing techniques
types of visualisation