focus all one's attention on a particular object or activity
she couldn't concentrate on the film
a threatened tax rise concentrates the mind wonderfully
gather (people or things) together in a common location
the nation's wealth was concentrated in the hands of the governing elite
increase the strength or proportion of (a substance or solution) by removing or reducing the other diluting agent or by selective accumulation of atoms or molecules
plants and microorganisms can concentrate metals from the environment