时速
shí sù · HSK 7
speed per hour
🚗⏱️ 时速 = 时 hour + 速 speed = speed per hour
时 means hour/time and 速 means speed or fast; together they name how much distance gets covered each hour. The same 速 shows up in 速度 (speed) and 高速 (high-speed).
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.