世界
せかい · sekai · JLPT N4 · noun
universe
🌍 世界 = generation (世) + boundary (界): all ages within all bounds
世 means generation or era (time), 界 means boundary or realm (space). The compound came from Buddhist Chinese, translating Sanskrit loka-dhatu: everything across time and space. Sound hook: sekai sounds like say-kai, as in say hi to the world.
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).