1 [mass noun] the rate at which someone or something moves or operates or is able to move or operate:we turned on to the runway and began to gather speedan engine running at full speed [count noun]:the car has a top speed of 147 mph
rapidity of movement or action:the accident was due to excessive speed
the rate at which something happens or is done:they were bemused by the speed of eventsthe course is delivered on CDROM so students can progress at their own speed
2each of the possible gear ratios of a bicycle.
US or dated each of the possible gear ratios of a motor vehicle.
3the light-gathering power or f-number of a camera lens.
the duration of a photographic exposure.
the sensitivity of photographic film to light.
4 [mass noun] informal an amphetamine drug, especially methamphetamine.
5 [mass noun] archaic success; prosperity:wish me good speed
1 [no object, with adverbial of direction] move quickly:I got into the car and home we sped
(past and past participle speeded) [no object] (of a motorist or vehicle) travel at a speed that is greater than the legal limit:the car that crashed was speeding
(past and past participle speeded) (speed up) move or work more quickly:you force yourself to speed up because you don’t want to keep others waiting
(past and past participle speeded) [with object] cause to move or happen more quickly:they sought to speed up decision-making
2 [with object] archaic make prosperous or successful:may God speed you
3 [no object] informal take or be under the influence of an amphetamine drug:more kids than ever are speeding, tripping, and getting stoned
quickly:a car flashed past them at speed
pick up (or get up) speed
(of a vehicle) go faster; accelerate:once out of the village, they picked up speed figurativethe debate has picked up steam recently
up to speed
1operating at full speed or at an expected rate or level:a noise like a jet engine coming up to speedthe manager is just getting up to speed
2 informal fully informed or up to date:his secretary’s up to speed on IT