Definition of concentrations:
(n) :
The act, process or ability of concentrating; the process of becoming concentrated, or the state of being concentrated.
(n) :
The direction of attention to a specific object.
(n) :
A field or course of study on which one focuses, especially as a student in a college or university.
(n) :
The proportion of a substance in a whole.
(n) :
(physical chemistry) The amount of solute in a solution measured in suitable units (e.g., parts per million (ppm))
(n) :
The act, process or product of reducing the volume of a liquid, as by evaporation.