A native Korean word (고유어, *goyueo*) with roots in Old Korean. The syllable *하* is thought to relate to concepts of "great" or "high," while *늘* may derive from an archaic root meaning "expanse" or "always." The word has remained remarkably stable across centuries of Korean writing.

하늘 carries deep cultural weight in Korean thought. In traditional Korean cosmology, 하늘 (Heaven) was a divine, governing force — the founding myth of Korea describes Dangun as the son of 환웅, who descended from 하늘. Even in everyday modern speech, Koreans say "하늘이 알고 땅이 안다" ("Heaven knows and the earth knows") to mean that nothing stays hidden forever. The word also appears in personal names (e.g., 하늘이), adding warmth and aspiration.