界
jiè · HSK 6
boundary
🚧 田 field + 介 between — the line where one field ends, a boundary
介 means intermediary or go-between. Place it under 田 field and you get the dividing line between plots — extended to any boundary, scope, or social circle.
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).