zhuàn​sù

rotational speed

转速 (轉速) zhuàn​sù
rotational speed noun
the rate of rotation of an object, typically measured in revolutions per minute (RPM) or as angular velocity

Frequency

Movie subtitles
0.600 per million appears in 0% of films
Written text
4.94 per million

Sources

Definitions
CC-CEDICT