accelerate

Formsaccelerates, accelerating, accelerated

1. 1
   verbintransitive

   To gain speed; to begin moving more quickly.

   The train accelerated smoothly out of the station.

   As traffic thinned, the bus began to accelerate.

   Similarspeed, quicken

   Oppositedecelerate, slow, brake

2. 2
   verbtransitive

   To cause something to move faster; to add to the speed of a moving object.

   A tailwind can accelerate a sailboat well beyond its usual pace.

   The pilot accelerated the aircraft down the runway.

   Similarspeed, quicken

   Oppositeslow, decelerate

   Note

   The core physical sense goes back to the Latin verb accelerō, built from ad and celer, "quick." The same celer gives English celerity. In this sense something does the speeding up to something else: a tailwind accelerates a boat, and a pilot accelerates a plane. Drop the object and the verb turns intransitive, as in the "gain speed" meaning, where the moving thing speeds up on its own.

3. 3
   verbtransitive

   To quicken the natural or ordinary course of a process.

   Higher temperatures accelerate the chemical reactions inside the battery.

   The new policy accelerated the decline of the old industry.

   Similarhasten, quicken, speed, expedite, hurry

   Oppositeslow, retard, delay

   Note

   Nothing physically moves here. The object is a process, and the verb speeds up its course: the growth of a plant, the increase of wealth, a work pace, the demand for air-conditioning. Keep the process as the object. When the process becomes the subject and no cause is named, as in "inflation accelerated," the verb has shifted to the intransitive "grow" sense.

4. 4
   verbtransitive

   To cause an event to happen sooner than it otherwise would; to hasten its occurrence.

   Her resignation accelerated the leadership contest.

   Mounting pressure can accelerate the calling of an election.

   Similarhasten, precipitate, expedite, advance, hurry

   Oppositedelay, postpone, defer

5. 5
   verbtransitive

   To cause something to change its velocity: that is, its speed, its direction of motion, or both.

   Like a foot on the gas pedal nudging a car to a higher speed: or the steering wheel changing where it heads.

   Strong magnets can accelerate charged particles to extremely high speeds.

   The pull of gravity accelerates a falling object toward the ground.

   Oppositedecelerate

   Note

   Physics gives the word a wider reach than everyday speech does. Velocity includes direction, so a force that only turns a moving body accelerates it, and so does a force that slows it down. Under Newton's second law, any net force on a mass produces acceleration. Casually, accelerating means speeding up, but in a physics context braking and steering count too.

6. 6
   verbintransitive

   To grow or increase, especially at an increasing rate.

   Inflation accelerated sharply during the final quarter.

   Membership numbers continue to accelerate year after year.

   Similarquicken, increase, rise, grow, surge

   Oppositeslow, decelerate

7. 7
   verbtransitive

   To enable a student to complete a course of study in less than the usual time.

   Special programs can accelerate motivated students toward early graduation.

   The school accelerated the twins through the curriculum after they tested ahead.

   Similaradvance, fast-track

   Note

   In schools the word moves a person, not a vehicle. The object is the student, and the usual construction is accelerate someone through a curriculum or toward early graduation. It is typically a response to demonstrated readiness. Keep it apart from speeding up a process: accelerating a course means running it faster, while accelerating a student means letting that student finish sooner.

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