Hatha yoga

Hatha yoga is the branch of yoga that works through the body, using postures, breath control and physical techniques to prepare the mind for meditation. The Sanskrit word hatha means force or effort, and in studios today a hatha class usually means a gentle, general class that holds each pose for a few breaths.
The word
Hatha is a Sanskrit word meaning force, effort or determination. Hatha yoga, then, is yoga done through effort: through the body and the breath, rather than through study or devotion alone. Almost every posture class today grows from it, including the beginner lessons I teach.
You will often hear that ha means sun and tha means moon, so that hatha yoga balances two opposite qualities. That reading appears in some later texts and is a nice image, but it is symbolism layered on top of the word. The literal meaning is force.
Where hatha yoga comes from
Hatha yoga appears in Sanskrit texts from about the eleventh century onward. Scholars working on these manuals, such as James Mallinson and Jason Birch, have traced how its techniques were gathered and handed down over several centuries in India.
The best known text is the Hatha Yoga Pradipika, written by Svatmarama in the fifteenth century. It draws on earlier works and organises the practice into four parts: asana (posture), pranayama (breath control), mudra and bandha (seals and locks), and nada (attention to inner sound). It also lists six cleansing practices, the shatkarmas. Its opening verses describe hatha yoga as a stairway to raja yoga, the meditative path of the Yoga Sutras. In other words, the body work was meant as preparation, not an end in itself.
Later manuals, including the Gheranda Samhita and the Shiva Samhita, expanded the list of postures and techniques. Even so, the classical hatha texts describe far fewer standing poses than a modern class uses.
How it shows up in a modern practice
Almost all posture-based yoga taught today descends from hatha yoga. Vinyasa, Ashtanga, Iyengar, Yin and Restorative all use postures, breath and focus that trace back to these texts, adapted during the twentieth century.
Studios use the word in a narrower sense. A class labelled “Hatha” usually means a general class at a steady pace: you come into a pose, hold it for a few breaths, come out, and rest before the next one. There may be simple breathing exercises (pranayama) at the start and a quiet rest at the end. If you want to compare it with other styles, see types of yoga.
Hatha yoga in a private lesson
The old manuals were written for a student learning directly from a teacher, and a private lesson keeps that shape. There is time to hold a pose long enough to feel it, to find the version that suits your body, and to add a few minutes of breathing before the final rest.
A lesson built this way suits people who want to learn the basic shapes properly before they move faster. My own training was a 200-hour course at House of Om in Bali; you can read about my training. The hatha texts build much of their breath work on prana, breath and the life it carries, and the Sanskrit yoga glossary explains the pose names you will hear.