concentrate

verb
  1. To focus all one's attention or mental effort on a particular object or activity. verb
    She couldn't concentrate on her work because of the noise.
    He needs to concentrate if he wants to pass the exam.
  2. To gather together or accumulate in a particular place. verb
    The troops were concentrated at the border.
    Pollutants tend to concentrate in the atmosphere.
  3. A substance made by removing or reducing the diluting agent; a concentrated form of something. noun
    The orange juice concentrate needs to be mixed with water before drinking.
    They used tomato paste as a concentrate for the sauce.