计时
jì shí · HSK 7
to measure time
⏱️ 计 (reckon/count) + 时 (time) = to count time, i.e. to time something
计 carries the sense of calculating or reckoning; pair it with 时 (time) and you get jì shí, putting a number on elapsed time. A 计时器 (jì shí qì) is literally a time-reckoning device: a stopwatch or timer.
计 — speech radical 讠 (言) + ten 十
计 is a semantic compound: 言 'speech/words' plus 十 'ten', suggesting counting or reckoning aloud. The original sense was to calculate or tally numbers, which extended to 'plan, scheme, plot' — any kind of mental reckoning. Modern uses like 计算 (calculate) and 计划 (plan) preserve both threads.
时 — sun 日 + temple/measure 寺
Originally a phono-semantic compound: 日 (sun) gives the meaning of time or season, while 寺 (shí) supplies the sound. Early forms used 之 as the phonetic before 寺 replaced it. The core sense 'season, time, hour' has stayed stable since ancient Chinese.