The Korean terms hyeong, pumsae and teul (meaning "form" or "pattern") are all used to refer to martial arts forms that are typically used in Korean martial arts such as Taekwondo and Tang Soo Do. In non-martial terms, hyeong 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.
The Kukkiwon uses the word pumsae for form. Pumsae philosophy originate from the book 'I Ching', a Chinese oracle. The I Ching has 64 hexagrams, a combination of two sets of three lines, closed or broken. The sets of three lines are called trigrams. The closed lines represent Yang, the open lines Yin. In the Chinese language, the unity of Yin and Yang is called 'taich'i'. In the Korean language, the unity is called Tae-geuk. This explains the term pumsae Taegeuk. The eight trigrams together are called Pal-gwe as in pumsae Palgwe.
Most Kukkiwon schools will use the pumsae Taegeuk whereas a few schools will use the pumsae Palgwe. The meanings, trigrams and symbols are shared by both pumsae Taegeuk and pumsae Palgwe, however the sequence of movements is different. The first 8 forms of the set of pumsae differ from each other, whereas the last 9 forms of the set are shared between the two sets.
Palgwe pumsae were used from 1967 to 1971. Taegeuk pumsae have been in use from 1971 to the present time. Kukkiwon states that Palgwe pumsae have been eliminated.
The official forms for Kukki-Taekwondo, as mandated by the Kukkiwon (World Taekwondo Headquarters), are the Taegeuk pumsae. Pumsae is sometimes written as poomse; however this would lead to an incorrect pronunciation as the Hangeul for the term uses the same Jamo as the Tae in Taekwondo, not the sound "Sey" (comparison: Teh-kwon-do not Tay-kwon-do nor Tie-kwon-do). However, many dialects of Korean pronounce the jamo ae and e almost identically. The Hanja for pumsae is .., and means "Quality Shapes of Strength"
On February 26, 1987, the Kukkiwon amended the spelling with it being interpreted as poomsae, which changed the Hanja character from the earlier "se" to the current "Sae". This also changed the meaning to one that is more complex. This has been reflected in the WTF World Poomsae Championships and of which the inaugural event was held in Seoul, South Korea in September 2006.