呼应
hū yìng · HSK 7
to echo
📣 呼 call + 应 respond = a call and its answer line up, they echo each other
应 — 广 (shelter) + 心 (heart) + 隹 (bird)
Originally written 應, this character combined a phonetic component with 心 (heart) to suggest 'responding from the heart' or 'answering a call'. The simplified form 应 keeps the top portion. Over time it broadened from 'respond/answer' to also mean 'should' or 'ought to'.