内蔵
ないぞう · naizou · JLPT N1 · na-adj
internal organ
内 = inside + 蔵 = storehouse: things stored inside the body or device
内 means inside and 蔵 means storehouse or to store. Together they give organs stored within the body, and also built-in parts of a device.
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').