concentration

plural concentrations

1. uncountableusuallyThe act, process or ability of concentrating; the process of becoming concentrated, or the state of being concentrated.

   The Koreans Almost all the Koreans in China live in the north-eastern provinces. The greatest concentration is found in an area of approximately 1,200 square miles in Kirin Province, an area which is part of the Yen-pien Korean Autonomous Chou.

   1972, Leo A. Orleans, Every Fifth Child: The Population of China, Stanford, CA: Stanford University Press, →ISBN, →LCCN, →OCLC, →OL, page 117

   1. uncountableusuallyThe direction of attention to a specific object.
   2. uncountableusuallyThe act, process or product of reducing the volume of a liquid, as by evaporation.
   3. uncountableusuallyThe act or process of removing the dress of ore and of reducing the valuable part to smaller compass, as by currents of air or water.
2. uncountableusuallyA field or course of study on which one focuses, especially as a student in a college or university.
3. uncountableusuallyThe proportion of a substance in a whole.

   The Koreans Almost all the Koreans in China live in the north-eastern provinces. The greatest concentration is found in an area of approximately 1,200 square miles in Kirin Province, an area which is part of the Yen-pien Korean Autonomous Chou.

   1972, Leo A. Orleans, Every Fifth Child: The Population of China, Stanford, CA: Stanford University Press, →ISBN, →LCCN, →OCLC, →OL, page 117

   1 more example

   Surprisingly, this analysis revealed that acute exposure to solvent vapors at concentrations below those associated with long-term effects appears to increase the risk of a fatal automobile accident. Furthermore, this increase in risk is comparable to the risk of death from leukemia after long-term exposure to benzene, another solvent, which has the well-known property of causing this type of cancer.

   2013 July-August, Philip J. Bushnell, “Solvents, Ethanol, Car Crashes & Tolerance”, in American Scientist

   1. physicaluncountableusuallychemistryThe amount of solute in a solution measured in suitable units (e.g., parts per million (ppm))
4. uncountableusuallyThe matching game pelmanism.