speed

American  

[speed] / spid /

noun

• speeds
  plural

1. rapidity in moving, going, traveling, proceeding, or performing; swiftness; celerity: the speed of sound.

   the speed of light;

   the speed of sound.

   Synonyms:

   hurry, expedition, dispatch, alacrity, fleetness

   Antonyms:

   slowness

2. relative rapidity in moving, going, etc.; rate of motion or progress.

   full speed ahead.

   Synonyms:

   hurry, expedition, dispatch, alacrity, fleetness

3. full, maximum, or optimum rate of motion.

   The car gets to speed in just nine seconds.

4. Automotive. a transmission gear ratio.

5. Photography.

   1. Also called film speed.  the sensitivity of a film or paper to light, measured by an ASA or DIN index, which assigns low numbers to slow film and higher numbers to faster film.

   2. Also called shutter speed.  the length of time a shutter is opened to expose the film or digital sensor inside the camera to light.

   3. the largest opening at which a lens can be used.

6. Slang. a stimulating drug, as caffeine, ephedrine, or especially methamphetamine or amphetamine.

7. Informal. a person or thing that is compatible with or typical of one's ability, personality, desires, etc..

   My speed is writing postcards on the porch while everyone else is tearing around the tennis court.

8. Archaic. success or prosperity.

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verb (used with object)

• speeds,
  present (3rd person singular)
• sped,
  past participle,  past
• speeded,
  past participle,  past (especially British)
• speeding
  present participle

1. to promote the success of (an affair, undertaking, etc.); further, forward, or expedite.

   Synonyms:

   favor, facilitate, advance

2. to direct (the steps, course, way, etc.) with speed.

3. to increase the rate of speed of (usually followed byup ).

   to speed up industrial production.

   Synonyms:

   accelerate

4. to bring to a particular speed, as a machine.

5. to cause to move, go, or proceed with speed.

6. to expedite the going of.

   to speed the parting guest.

7. Archaic. to cause to succeed or prosper.

verb (used without object)

• speeds,
  present (3rd person singular)
• sped,
  past participle,  past
• speeded,
  past participle,  past (especially British)
• speeding
  present participle

1. to move, go, pass, or proceed with speed or rapidity.

2. to drive a vehicle at a rate that exceeds the legally established maximum.

   He was arrested for speeding.

3. to increase the rate of speed or progress (usually followed byup ).

4. to get on or fare in a specified or particular manner.

5. Archaic. to succeed or prosper.

idioms

1. at full / top speed,

   1. at the greatest speed possible.

      We drove down the highway at full speed.

   2. to the maximum of one's capabilities; with great rapidity.

      He worked at full speed.

2. up to speed,

   1. operating at full or optimum speed.

   2. functioning or producing at an expected, acceptable, or competitive level; up to par.

      a new firm not yet up to speed.

speed British  

/ spiːd /

noun

1. the act or quality of acting or moving fast; rapidity

2. the rate at which something moves, is done, or acts

3. physics a scalar measure of the rate of movement of a body expressed either as the distance travelled divided by the time taken ( average speed ) or the rate of change of position with respect to time at a particular point ( instantaneous speed ). It is measured in metres per second, miles per hour, etc

4. a rate of rotation, usually expressed in revolutions per unit time

5. 1. a gear ratio in a motor vehicle, bicycle, etc

   2. ( in combination )

      a three-speed gear

6. photog a numerical expression of the sensitivity to light of a particular type of film, paper, or plate See also ISO rating

7. photog a measure of the ability of a lens to pass light from an object to the image position, determined by the aperture and also the transmitting power of the lens. It increases as the f-number is decreased and vice versa

8. a slang word for amphetamine

9. archaic prosperity or success

10. quickly

11. 1. operating at an acceptable or competitive level

    2. in possession of all the relevant or necessary information

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verb

1. to move or go or cause to move or go quickly

2. (intr) to drive (a motor vehicle) at a high speed, esp above legal limits

3. (tr) to help further the success or completion of

4. slang (intr) to take or be under the influence of amphetamines

5. (intr) to operate or run at a high speed

6. archaic

   1. (intr) to prosper or succeed

   2. (tr) to wish success to

speed Scientific  

/ spēd /

1. The ratio of the distance traveled by an object (regardless of its direction) to the time required to travel that distance.

2. Compare velocity

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speed More Idioms  

More idioms and phrases containing speed

• full speed ahead
• up to par (speed)

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Synonym Usage

Speed, velocity, quickness, rapidity, celerity, haste refer to swift or energetic movement or operation. Speed (originally prosperity or success) may apply to human or nonhuman activity and emphasizes the rate in time at which something travels or operates: the speed of light, of a lens, of an automobile, of thought. Velocity, a more learned or technical term, is sometimes interchangeable with speed : the velocity of light; it is commonly used to refer to high rates of speed, linear or circular: velocity of a projectile. Quickness, a native word, and rapidity, a synonym of Latin origin, suggest speed of movement or operation on a small or subordinate scale; quickness applies more to people ( quickness of mind, of perception, of bodily movement ), rapidity more to things, often in a technical or mechanical context: the rapidity of moving parts; a lens of great rapidity. Celerity, a somewhat literary synonym of Latin origin, refers usually to human movement or operation and emphasizes expedition, dispatch, or economy in an activity: the celerity of his response. Haste refers to the energetic activity of human beings under stress; it often suggests lack of opportunity for care or thought: to marry in haste; a report prepared in haste. See rush ¹.

Other Word Forms

Derived Forms

• speeder
  noun
• speedfulness
  noun
• speedingness
  noun
• overspeed
  verb
• outspeed
  verb (used with object)
• multispeed
  adjective
• speedful
  adjective
• speedless
  adjective
• speedfully
  adverb
• speedingly
  adverb

Inflected Forms

Nouns

• speeds
  plural

Participles

• speeding
  present
• sped
  past
• speeded
  past

Conjugated Forms

Present

• speed
  simple
• speeds
  simple
• have sped
  perfect
• have speeded
  perfect
• has sped
  perfect
• has speeded
  perfect
• am speeding
  progressive
• are speeding
  progressive
• is speeding
  progressive
• have been speeding
  perfect progressive
• has been speeding
  perfect progressive

Past

• sped
  simple
• speeded
  simple
• had sped
  perfect
• had speeded
  perfect
• was speeding
  progressive
• were speeding
  progressive
• had been speeding
  perfect progressive

Future

• will speed
  simple
• will have sped
  perfect
• will have speeded
  perfect
• will be speeding
  progressive
• will have been speeding
  perfect progressive

Etymology

Origin of speed

First recorded before 900; 1965–70 speed for def. 6; (noun) Middle English spede “good luck, prosperity, rapidity,” Old English spēd; cognate with Dutch spoed, Old High German spōt; akin to Old English spōwan “to prosper, succeed”; (verb) Middle English speden “to succeed, prosper, go with speed,” Old English spēdan “to succeed, prosper”; cognate with Old Saxon spōdian, Old High German spuoten

Explanation

Speed most often describes acceleration or a high rate of motion. When something picks up too much speed, it can run off course, like a kid on a bike zooming uncontrollably down a steep hill. Speed can be a noun or verb. As a noun, it's an indicator of pace, as in the speed of a car. As a noun, it's also a drug that keeps you awake, very awake. As a verb, it means to “move along quickly,” like how you speed around on your bike. A fun fact: while speed refers to the distance traveled by an object during a specific amount of time, velocity describes that distance, but in a specified direction.

Example Sentences

See Examples For:

speed speeds sped speeded speeding

But under the constant watch of phone cameras and gossip that travels at the speed of social media feeds, they face greater pressures.

From Salon ● Sep. 24, 2026

"There's sort of a smooth trend and then suddenly for lowest-metallicity stars, the wind speed really drops off," Telford said.

From Science Daily ● Sep. 24, 2026

"He's really good. He's special. Very fast, very talented and he countered whatever I tried with his speed and timing," said Hrgovic.

From BBC ● Sep. 23, 2026

The move to speed new products is a contrast from Trump’s first term, when the FDA banned fruit-flavored vapes in an effort to curb teen use.

From The Wall Street Journal ● Sep. 23, 2026

The Butterfly moved it in a quick arc, and with a speed I wouldn’t have thought possible, that flickering speck of light leaped from that lighter to the wall of the ship’s passageway and ignited.

From "Glitch" by Laura Martin

In Maine, Navatek was studying ways to modify small boats to reduce the “slamming” impact felt by passengers at high speeds.

From Salon ● Sep. 23, 2026

But over the weekend, she saw campervans, a large coach and cars with trailers - one towing a boat - all drive down it, some at speeds as fast as 40mph.

From BBC ● Sep. 22, 2026

Earlier methods also produced muonium atoms traveling at different speeds and in many directions, making them poorly suited for extremely precise gravity measurements.

From Science Daily ● Sep. 18, 2026

To counter the fast-flying drones, Kyiv is racing to develop jet-powered interceptor drones that travel at high speeds to knock them off course.

From The Wall Street Journal ● Sep. 17, 2026

Malik laughs as his Mario speeds by my Toad.

From "On the Come Up" by Angie Thomas

Meta has sped up the pace of its AI launches recently, Anmuth added.

From MarketWatch ● Sep. 22, 2026

It comes as the passthrough of wholesale prices to retail prices has sped up for gas prices overall, but less intensely for electricity, with variation among different countries remaining in both cases, they say.

From The Wall Street Journal ● Sep. 22, 2026

A more traditional stride can be sped up or slowed down.

From Los Angeles Times ● Sep. 16, 2026

He came closest to levelling when he sped beyond the Brighton defence, but his shot was saved by Jason Steele.

From BBC ● Sep. 16, 2026

The canoe righted itself and sped through the water.

From "Carry On, Mr. Bowditch" by Jean Lee Latham

Out-of-pocket expenses for things like exam fees were also to be covered, while progression through the five resident doctors pay bands was to be speeded up.

From BBC ● Mar. 30, 2026

The deputy council leader also welcomed the overhaul plans from the UK government, saying the process has "always needed to be speeded up".

From BBC ● Aug. 24, 2025

It wasn’t long before USC finally speeded away from Iowa, with Desmond Claude and Saint Thomas taking control to close out the Hawkeyes.

From Los Angeles Times ● Jan. 15, 2025

But the biggest thing Ghai and his family are doing does not directly involve workers at all: They’ve speeded up and expanded their use of technology, especially AI.

From Los Angeles Times ● May 1, 2024

He hated athletics because it speeded up the process of sweat.

From "The Chocolate War" by Robert Cormier

But caution should be aimed at speeding safe AI, not slowing the most advanced AI.

From MarketWatch ● Sep. 22, 2026

OpenAI and Anthropic might help by speeding up their IPOs, making them more responsive to a broad shareholding public rather than their highly ideologized and oddball founders.

From The Wall Street Journal ● Sep. 18, 2026

As I watched rows of identical-looking loaves speeding along the conveyer I thought about Russia's parliament.

From BBC ● Sep. 17, 2026

During the Grossman trial, a California Highway Patrol officer testified that he stopped her for speeding and warned that her that driving above the speed limit could have fatal consequences.

From Los Angeles Times ● Sep. 17, 2026

Had I lived a different life, getting thrown out of a speeding minibus might have fazed me.

From "Born a Crime: Stories from a South African Childhood" by Trevor Noah

Related Words

• advance
• boost
• expedite
• facilitate
• fly
• further
• hasten
• help
• hurry
• promote
• quicken
• ride
• run
• rush
• zoom