1 : the rate at which someone or something moves or travels [noncount] ▪ The trucks gain/gather speed as they drive down the hill. = The trucks pick up speed as they drive down the hill. [=the trucks go faster as they drive down the hill] ▪ This instrument measures wind speed. ▪ He was running at full/top speed. [=as fast as possible] ▪ The machine was operating at high/medium/low speed. ▪ traveling at nearly the speed of light/sound [count] ▪ Under the right conditions the car can reach speeds over 200 miles an hour. ▪ The vehicle maintained a speed of 40 miles per hour. 2 : the rate at which something happens or is done [noncount] ▪ The work was done with remarkable speed. ▪ They ate their lunch at lightning speed. [=extremely quickly] [count] ▪ This computer works at a much faster processing speed than my old one. ▪ He types at a speed of about 50 words per minute. = His typing speed is about 50 words per minute. 3 [noncount] : the quality of being quick
▪ The machine chops up tree branches and leaves with speed and ease. 4 [count] photography a : a measurement that indicates how quickly film reacts to light and that is expressed as a number (such as 100 or 200)
▪ 200 speed film
b : the time during which a camera's shutter is open
▪ faster/slower shutter speeds 5 [count] : a gear in a vehicle or bicycle
▪ a three-speed bicycle ▪ Her old car has four speeds. 6 [noncount] informal : an illegal drug that makes a person feel more excited and full of energy
▪ He was high on speed.