境界
jìngjiè · HSK 7
extent reached
🚧 境 (boundary) + 界 (border) = a doubled-up boundary line marking how far a state or extent reaches
界 — field 田 + scope 介
界 combines 田 (field) as the semantic component with 介 (jiè) as the phonetic. The original sense referred to boundaries between fields, then broadened to any border, limit, or realm — yielding modern meanings like 'world' (世界) and 'boundary' (边界).