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

If present, primordial magnetic fields would speed up recombination by pushing and pulling on charged particles, making matter slightly clumpy.

From Science Daily ● Oct. 4, 2026

Governing body the FIA said this was caused by a combination of the weather, low speed, the mandated wet-weather energy management settings and the circuit layout.

From BBC ● Oct. 4, 2026

The following breakdown showing the Boeing 737 MAX’s speed, angles and G-force loads is based on second-by-second satellite tracking data from Flightradar24.

From The Wall Street Journal ● Oct. 3, 2026

“Just continuing to come in and work on it. The jumper, I’ve been in the gym all summer working on fluidity and the speed of my release, stuff like that, moving,” James said.

From Los Angeles Times ● Oct. 3, 2026

The wind would be at their backs and he might be able to pick up speed.

From "Storm Runners" by Roland Smith

Vortices can travel at speeds of tens of kilometers per second, but over the span of a picosecond they move only tens of nanometers.

From Science Daily ● Oct. 2, 2026

It can travel driverless from a rail depot to a station at speeds of up to 40 kilometres per hour.

From Barron's ● Oct. 2, 2026

Zhu noted that while the processing power of chips has gotten exponentially faster, network bandwidth speeds haven’t kept pace.

From MarketWatch ● Sep. 30, 2026

The filters clog at low speeds or cold temperatures; burner units pack up; the sensors break constantly.

From The Wall Street Journal ● Sep. 24, 2026

Well, she speeds as well as she can as she watches where she steps, nervous sweat pouring down her sides, her heart beating in terror.

From "A Heart in a Body in the World" by Deb Caletti

Donald Trump then sped off in the presidential limo known as the Beast — at nearly 100 mph, according to pool reports — and headed for an event in Oklahoma.

From Salon ● Oct. 2, 2026

The economy also appears to have sped up, further reducing the need to resort to layoffs.

From MarketWatch ● Oct. 1, 2026

People walking on the boardwalk narrowly evaded getting hit, with one woman jumping over the railing just in time before the car sped by.

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

Pure panic had sped me out of Camilla’s cabin.

From "Secrets at Sea" by Richard Peck

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

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

He says inquiries could also be speeded up if they are placed on a non-statutory rather than statutory footing.

From BBC ● Sep. 15, 2024

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

As I approached the classroom, he speeded up, coming closer to me.

From "Warriors Don't Cry: A Searing Memoir of the Battle to Integrate Little Rock's Central High" by Melba Pattillo Beals

"It's hard to overstate how dangerous speeding towards RSI is," Wang posted in response to Coxon's resignation, referring to recursive self-improvement, which is a technique where software is designed to continuously teach itself.

From Barron's ● Oct. 2, 2026

Los Angeles drivers will have a harder time getting away with speeding come Halloween, with 125 cameras scheduled to be installed throughout the city to catch those driving over the speed limit.

From Los Angeles Times ● Oct. 1, 2026

For the speeding offence, Richie entered a guilty plea in writing and his case was dealt with in private via the Single Justice Procedure, external.

From BBC ● Sep. 30, 2026

I’m not advocating for speeding, but you’re not bound by the confines of traffic, where you have a stoplight at every block.

From Slate ● Sep. 28, 2026

There’s a bicyclist or two or twenty, speeding home after work, their wheels zizzing by her.

From "A Heart in a Body in the World" by Deb Caletti

Related Words

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