pumppump1 /pʌmp/ ●●○ noun [countable] 1 a machine that forces liquid or gas into or out of something: a water/fuel/gas etc. pump a bicycle pump2a woman’s plain shoe that does not fasten: a pair of black pumps3also gas pump a machine at a gas station, used to put gasoline into a car [Origin: (1) 1400–1500 Middle Low German pumpe or Middle Dutch pompe]