kekkai
Kekkai is a Japanese term meaning barrier, boundary, or ward. It can be written with various kanji, most commonly 結界 or 血界, and refers to a protective circle, seal, or territory that delineates or separates spaces, often to keep danger out or to contain other realms.
Etymology and usage: The word combines elements meaning to bind or tie (結) and world or boundary (界).
In popular culture: The term is widely used in manga, anime, and games to denote magical barriers
Other uses: Beyond fiction, kekkai appears in fantasy settings and role-playing games as a mechanic or narrative
See also: ward, seal, barrier (magic), Shinto purification, onmyodo.