お代わり
おかわり · okawari · JLPT N2 · noun
helping
🍚🍵 お + 代わり = polite + replacement: a refill takes the empty bowl's place
代わり (kawari) comes from 代わる, to replace or take turns, and お makes it polite. An お代わり is another serving in place of the one you finished. In restaurants, お代わり自由 means free refills.
代 — person radical 亻 + 弋 (stake/dart, phonetic)
代 is a semantic-phonetic compound: 亻 (person) gives the meaning and 弋 supplies the sound. The original sense was one person taking the place of another, which broadened to 'substitute,' 'replace,' and then 'generation' or 'era' — successive groups of people replacing the previous.