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Velocity

vuh-LOSS-ih-tee /vəˈlɒsɪti/

nounB2GRESAT

FormalScientific

The speed of something in a given direction.

Crucially, velocity is a vector quantity, meaning it has both magnitude (speed) and direction. Two objects can have the same speed but different velocities if they are moving in different directions.

The story behind the word. "Velocity" comes from the Latin word "velocitas," meaning "swiftness" or "rapidity." This, in turn, is derived from "velox," meaning "swift" or "rapid." So, from its very roots, the word has been about quickness, with the directional aspect added by scientific definition.

Word relationships

speed: "Speed" refers only to the magnitude of motion (how fast), while "velocity" includes direction.

rest: A state of zero velocity.
stillness: Absence of motion, implying zero velocity.

Commonly confused with

Speed: Speed is a scalar (magnitude only), velocity is a vector (magnitude and direction).

Word family

velocious (adjective): Swift; rapid (less common).

Collocations

constant velocity
initial velocity
terminal velocity
escape velocity
relative velocity

Idioms & expressions

at full velocity

Example sentences

"The projectile's initial velocity was 500 meters per second eastward." Explaining a physics concept.
"The velocity of light in a vacuum is a fundamental physical constant." From a scientific article. (Scientific American)

Memory hook

Imagine a VELVET-clad race car driver, known for his incredible VELOCITY on the track. Velvet Velocity

When not to use

Do not use "velocity" if you only mean "speed" without any directional component. For example, "The car's speed limit is 60 mph" is correct, not "The car's velocity limit..."

Fun facts

The term 'velocity' was popularized in scientific discourse by Galileo Galilei in the 17th century.
The escape velocity from Earth is about 11.2 kilometers per second (25,000 mph).