velocity
/vɪˈlɒsətɪ/noun
(pl. -ies)
1- the speed of something in a given direction速度, 速率：
the velocities of the emitted particles.
发射粒子的速率。
1.1
- (in general use) speed（普通用语）速度：
the tank shot backwards at an incredible velocity.
坦克以令人难以置信的速度后退。
1.2
- （亦作velocity of circulation）Economics the rate at which money changes hands within an economy【经济】周转率, 流通速度。
词源
late Middle English: from French vélocité or Latin velocitas, from velox, veloc- 'swift'.