比重
ひじゅう · hijuu · JLPT N1 · noun
specific gravity
比 — two 匕 (person) side by side
比 is a pictograph showing two people standing side by side, facing the same direction. From this image of paired figures came the core meaning 'to compare' or 'to be next to,' since comparing things naturally involves placing them alongside each other.
重 — person 人 + east 東 (phonetic)
Originally depicted a person carrying a heavy bundle on their back, suggesting weight and burden. The 東-like element served as a phonetic component. Over time the character split into two readings: zhòng meaning 'heavy' and chóng meaning 'repeat/again'.