体积
tǐjī · HSK 5
volume
📦 体积 = body (体) + accumulate (积) → bulk a body takes up
体 means body or physical form; 积 means to accumulate or pile up. Together they name the space a body occupies — its volume or bulk. Compare 面积 (area = surface + accumulate).
积 — grain radical 禾 + 责 (phonetic)
积 is a semantic-phonetic compound: 禾 (grain) gives the meaning, while 责 supplies the sound. It originally referred to piling up harvested grain, which extended to the general sense of 'accumulate' or 'amass'. The simplified form replaced the older 積.