Noun

(en-noun)

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

# The direction of attention to a specific object.

# The act, process or product of reducing the volume of a liquid, as by evaporation.

# The 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.

A field or course of study on which one focuses, especially as a student in a college or university.

The proportion of a substance in a whole.

* {{quote-magazine, year=2013, month=July-August, author= Philip J. Bushnell, magazine=(American Scientist)

, title= Solvents, Ethanol, Car Crashes & Tolerance , passage=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.}}

# (chemistry) The amount of solute in a solution measured in suitable units (e.g., parts per million (ppm))

The matching game pelmanism.

Noun

(wikipedia prozone) (en noun)

(immunology) The range of antibody concentrations within which reaction is inhibited