In chemistry, concentration refers to a measurement of how much substance (or solute) exists within a certain volume (or solvent).[1] A solution is said to be saturated when the solvent is unable to dissolve more solute.
In psychology, concentration as a cognitive process means focusing selectively on a single aspect of one's environment or thoughts while ignoring other things.
In Buddhistmeditation, concentration means focusing the mind selectively on a single aspect of one's thoughts or images while letting go of all other things until the mind become "single-pointed" ("samadhi") through relaxed focused awareness ("shamatha"). According to Buddhism, concentration is related to the "fire element" of the mind and nervous system.