A metaphor is a figurative language device that represents one thing as if it were another, or compares two things not normally viewed as similar, such as time is a thief. This comparison draws attention to the way time is quick and stealthy. Simile
Velocity is the rate of motion, speed or action. An example of velocity is a car driving at 75 miles per hour. velocity. pl. velocity. pl. Rapidity or speed of motion; swiftness. Physics A vector quantity whose magnitude is a body's speed and whose direction is the body's direction of motion.
Speed is a scalar (dimensionless) quantity, while velocity is a vector quantity consisting of speed and direction. We might say a car is traveling at 20 m/s, and this tells us its speed. Or we might say the car is traveling at 20 m/s at a compass bearing of 25 degrees (north-by-northeast); this tells us its velocity.