deceleration

/ˌdiːseləˈreɪʃn/ (bre, ipa) · /ˌdiːseləˈreɪʃn/ (ame, ipa) · /(ˌ)dē-ˌse-lə-ˈrā-shən/ (ame, mw)

deceleration — noun

  • decelerationsingular
  • decelerationsplural

1. a drop in how fast a vehicle, projectile, or moving body travels — for example,

1.名詞C1
釋義

a drop in how fast a vehicle, projectile, or moving body travels — for example, when a car brakes or a falling object meets resistance.

例句

The pilot felt a sharp deceleration as the plane touched down on the runway.

collocation: sharp/sudden deceleration

Yasmin's instructor measured the car's deceleration during the emergency braking test.

deceleration of [vehicle] in physics / driving context

同義詞
  • slowdown

    more general; can describe non-physical pace too

  • braking

    specifically when caused by a brake mechanism

  • retardation

    technical physics term; can sound dated in everyday use

反義詞
  • acceleration

    the increase in speed; the direct opposite in physics

文法句型

deceleration of [object]

rapid/gradual/sudden deceleration

用法筆記

Subject is usually a vehicle, aircraft, or projectile. Often paired with adjectives describing rate (sharp, gentle, rapid, gradual).

常見錯誤

❌The car had a deceleration to stop.
✅The car decelerated to stop.
💡use the verb 'decelerate' for the action; 'deceleration' is the noun describing the rate or event.

2. a slowing in the pace at which an activity, change, or process moves forward — f

2.名詞C1
釋義

a slowing in the pace at which an activity, change, or process moves forward — for example, growth, sales, reforms, or a project's progress.

例句

Analysts predicted a sharp deceleration in housing sales after the new tax took effect.

deceleration in [economic activity]

Salma reported a clear deceleration in the team's progress on the bridge project.

deceleration in [project/work progress]

同義詞
  • slowdown

    common in business writing; near-interchangeable

  • downturn

    stronger; suggests an active reversal, not just slowing

  • easing

    softer; suggests a welcome or controlled slowing

反義詞
  • acceleration

    speeding up of the same process or activity

  • expansion

    growth in scale or activity, often economic

文法句型

deceleration in [activity/process]

deceleration of [growth/economy/progress]

用法筆記

Distinguish from sense 1: this sense applies to abstract processes (growth, sales, output, reforms), not physical motion. Common in business and economic reporting.

常見錯誤

❌There was a deceleration in the room.
✅There was a deceleration in conversation.
💡this sense needs an abstract process or activity as its object, not a static place.