Pump in Definition 1 of 2Pro Tip 1/3Physical Transfer Used when referring to the actual movement of a substance through space, often by machinery. The plant pumps in coolant to prevent overheating. Pro Tip 2/3Continuous Action Describes an ongoing or sustained action, not just a one-time event. We need to keep pumping in fresh oxygen for the patients. Pro Tip 3/3Necessity or Improvement Suggests adding something essential or to enhance something that already exists. The greenhouse pumps in extra CO2 to boost plant growth.