Velocity

Part of speech: noun (n.)

1. Quickness of motion; swiftness; speed; celerity; rapidity; as, the velocity of wind; the velocity of a planet or comet in its orbit or course; the velocity of a cannon ball; the velocity of light.

2. Rate of motion; the relation of motion to time, measured by the number of units of space passed over by a moving body or point in a unit of time, usually the number of feet passed over in a second. See the Note under Speed. Angular velocity. See under Angular. -- Initial velocity, the velocity of a moving body at starting; especially, the velocity of a projectile as it leaves the mouth of a firearm from which it is discharged. -- Relative velocity, the velocity with which a body approaches or recedes from another body, whether both are moving or only one. -- Uniform velocity, velocity in which the same number of units of space are described in each successive unit of time. -- Variable velocity, velocity in which the space described varies from instant, either increasing or decreasing; -- in the former case called accelerated velocity, in the latter, retarded velocity; the acceleration or retardation itself being also either uniform or variable. -- Virtual velocity. See under Virtual.

Synonyms: Swiftness; celerity; rapidity; fleetness; speed.