1.
sacred boundary, spiritual barrier
In Buddhism, a ritually defined area that marks the boundary of a sacred space, keeping impurity out and sanctity in. Used at temples and during religious ceremonies.
2.
magical barrier, force field
In anime, manga, and games, a supernatural protective barrier that blocks enemies or contains power. This is the more widely known meaning among younger speakers.
Usage
The original Buddhist sense refers to a ritually purified boundary. In modern pop culture, the word has become extremely common in anime and manga to mean a magical force field or protective barrier. The key collocation 結界を張る (to put up a barrier) is used in both senses.
Etymology
From Buddhist terminology. 結 means "to bind" and 界 means "boundary" — a bound or established boundary separating sacred from profane space.
Common collocations
Related Words
Compare:
魔法陣 (magic circle)