The Korean terms hyeong, pumsae and teul (meaning "form" or "pattern") are all used to refer to martial arts used in Taekwondo. In non-martial terms, hyung () can mean "big brother," but this is fundamentally distinct from hyeong (). Hyeong is often romanized as hyung; pumsae is often romanized as poomsae or poomse; and teul is often romanized as tul.

A hyeong is a systematic, prearranged sequence of martial techniques that is performed either with or without the use of a weapon. In traditional dojangs (training halls), hyeong are used primarily as a form of interval training that is useful in developing mushin, proper kinetics and mental and physical fortitude. Hyeong may resemble combat, but are artistically non-combative and woven together so as to be an effective conditioning tool. One's aptitude for a particular hyeong may be evaluated in competition.

A practitioner of Tae Kwon-Do is responsible for knowing his current ‘test’ form(s) as well as all the forms he/she has learned up till that point.

At higher rank testing the judges can request the student testing to perform any form from their rank and below.