1. a rate (usually rapid) at which something happens

    Synonyms : fastness, swiftness
    Type Of : rate, pace
    Examples :
    • the project advanced with gratifying speed
  2. a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression

    Synonyms : amphetamine, pep pill, upper
    Type Of : drug of abuse, stimulant drug, excitant, stimulant, street drug
  3. cause to move faster

    Synonyms : accelerate, speed up
    Type Of : modify, alter, change
  4. move hurridly

    Synonyms : belt along, bucket along, cannonball along, hasten, hie, hotfoot, pelt along, race, rush, rush along, step on it
    Type Of : travel, locomote, go, move
  5. changing location rapidly

    Synonyms : hurrying, speeding
    Type Of : move, movement, motion
  6. move very fast

    Synonyms : hurry, travel rapidly, zip
    Type Of : move, travel, go, locomote
    Examples :
    • The runner zipped past us at breakneck speed
  7. move faster

    Synonyms : accelerate, quicken, speed up
    Type Of : deepen, intensify
  8. the ratio of the focal length to the diameter of a (camera) lens system

    Synonyms : f number, focal ratio, stop number
    Type Of : ratio
  9. distance travelled per unit time

    Synonyms : velocity
    Type Of : rate
  10. travel at an excessive or illegal velocity

    Type Of : move, go, travel, locomote
    Examples :
    • I got a ticket for speeding