con·cen·tra·tion 
(kŏn′sən-trāshən)
(kŏn′sən-trāshən)n.
1.
a. The act or process of concentrating, especially the fixing of close, undivided attention.
b. The condition of being concentrated.
2. Something that has been concentrated.
3. Chemistry The amount of a specified substance in a unit amount of another substance.