内部
ないぶ · naibu · JLPT N1 · noun
inside
🏠 内 (inside) + 部 (part) = the inside part of something
内 means inside, and 部 means part or section. Joined, they describe the inner part of a thing, as in an interior or internal structure. The same 内 appears in 内側 (inner side).
内 — enclosure 冂 + enter 入
内 originally depicted something entering (入) into an enclosed space (冂), giving the core sense of 'inside' or 'within'. The pictographic image of going into a covered area extended naturally to meanings like inner, internal, and inland. It contrasts with 外 ('outside').
部 — 阝(邑) right + 咅 phonetic
The right-side 阝 derives from 邑 (city/settlement), giving the meaning of a region, district, or administrative division. The left side 咅 supplies the sound. Originally referring to a settlement, the meaning broadened to 'part,' 'section,' or 'ministry.'