原子
げんし · genshi · JLPT N1 · noun
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🔬 原 = origin + 子 = little one: the tiny original building block
原 means origin or source, and 子 here works as a suffix for a small thing. Together they name the smallest original unit of matter, the base that everything else is built from.
原 — cliff 厂 + spring 泉 (white 白 + water 水)
Originally a pictograph showing a spring of water flowing out from beneath a cliff, depicting the source of a stream. From this concrete image of a water source, the meaning extended to 'origin,' 'source,' and 'original.' A separate character 源 was later created with the water radical 氵 to keep the literal 'spring' sense.
子 — pictograph of a baby/child with arms out
子 began as a pictograph of a swaddled infant with a large head and outstretched arms, originally meaning 'baby' or 'child.' From there it broadened to 'son,' 'offspring,' and a respectful suffix for masters like 孔子 (Confucius). It also became one of the twelve earthly branches.