1. (

• speed ,
• velocity

) distance travelled per unit time ;

2. (

• speed ,
• swiftness ,
• fastness

) a rate (usually rapid) at which something happens; "the project advanced with gratifying speed" ;

3. (

• speed ,
• speeding ,
• hurrying

) changing location rapidly ;

4. (

• focal_ratio ,
• f_number ,
• stop_number ,
• speed

) the ratio of the focal length to the diameter of a (camera) lens system ;

5. (

• amphetamine ,
• pep_pill ,
• upper ,
• speed

) a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression ;

1. (

• rush ,
• hotfoot ,
• hasten ,
• hie ,
• speed ,
• race ,
• pelt_along ,
• rush_along ,
• cannonball_along ,
• bucket_along ,
• belt_along ,
• step_on_it

) move hurridly; "He rushed down the hall to receive his guests"; "The cars raced down the street" ;

2. (

• accelerate ,
• speed_up ,
• speed ,
• quicken ,

) move faster; "The car accelerated" ;

3. (

• travel_rapidly ,
• speed ,
• hurry ,
• zip

) move very fast; "The runner zipped past us at breakneck speed" ;

4. (

• speed ,

) travel at an excessive or illegal velocity; "I got a ticket for speeding" ;

5. (

• accelerate ,
• speed ,
• speed_up ,

) cause to move faster; "He accelerated the car" ;