回路
かいろ · kairo · JLPT N1 · noun
circuit
⚡🔌 回 (go round) + 路 (road) = a road the current loops around; a closed electric loop
回 means turn or loop back, and 路 means road or path. Electricity travels a path that loops back to its source, which is what a circuit is.
回 — enclosure 囗 + smaller 囗 inside
回 is a pictograph of a swirling whirlpool or coiled spiral, shown as nested squares in modern form. The original meaning was 'to revolve' or 'turn around,' which extended to 'return' and 'a time/occurrence.' It also appears as a phonetic in characters like 茴 and 廻.
路 — foot 足 + each 各 (phonetic)
路 is a semantic-phonetic compound. The foot radical 足 on the left signals meaning related to walking or travel, while 各 on the right hints at the ancient pronunciation. Originally referring to a road traveled on foot, it broadened to mean 'road, path, route' in general.