English Reference
noun

acceleration

n.
US /ˌækˌsɛɫɝˈeɪʃən/ UK /ɐksˌɛləɹˈeɪʃən/ ac·cel·er·a·tion UK spelling accelerations

  1. 01 B2 Upper Intermediate

    the act of moving faster or the process of something speeding up.

    the act of accelerating or the state of being accelerated; a general increase in the speed of motion or action.

    Simple

    The car's acceleration was so smooth that I didn't realize how fast we were going.

    In context

    The driver felt a sudden surge of acceleration as the vehicle merged onto the motorway, quickly reaching the speed of the surrounding traffic.

    speeding upquickening
  2. 02 B2 Upper Intermediate Technical Science

    the measurement of how quickly an object's speed or direction changes.

    the rate of change of velocity with respect to time, encompassing changes in both magnitude and direction.

    Simple

    In physics class, we calculated the acceleration of a ball rolling down a hill.

    In context

    The probe's acceleration was carefully monitored by ground control to ensure it entered the planet's orbit at the precise velocity required.

    Usage

    Often used as an uncountable noun in scientific contexts when referring to the concept rather than a specific value.

  3. 03 C1 Advanced AcademicFormal

    an increase in the speed at which something happens or develops.

    the advancement or hastening of a process, trend, or course of study.

    Simple

    The government promised an acceleration of the new housing project.

    In context

    Economists have noted a significant acceleration in the adoption of digital payment systems over the last fiscal quarter.

    Teacher's tip

    In educational contexts, this specifically refers to allowing gifted students to move through the curriculum faster than their peers.

    hasteningexpediting

Such lines form in response to the sharp acceleration in growth that takes place shortly after birth.

ScienceDaily· 13 Aug 2026

The slower one would be appropriate for stop-and-go traffic, since the quicker acceleration would make it difficult to match the speed of the cars around you.

Ars Technica· 5 Aug 2026

Etymology tree Proto-Indo-European *h₂éd Proto-Italic *ad Proto-Italic *ad- Latin ad- Proto-Indo-European *kel-der. Latin celer Proto-Indo-European *-h₂ Proto-Indo-European *-éh₂ Proto-Indo-European *-yéti Proto-Indo-European *-eh₂yéti Proto-Italic *-āō Latin -ō Latin celerō Latin accelerō Proto-Indo-European *-tisder. Proto-Italic *-tjō Latin -tiō Latin accelerātiōder. English acceleration First attested in 1531. From French accélération or more likely directly from Latin accelerātiō (“a hastening, acceleration”). Equivalent to accelerate + -ion.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin accelerātiō
Level B2 · Upper Intermediate
Frequency Frequent
Updated