What does the word concentration mean?

Usage examples for concentration

  1. Concentration demands interest and enthusiasm. – Analyzing Character by Katherine M. H. Blackford and Arthur Newcomb
  2. By volume, it is present in the amount of about one part in ten million, which is fairly heavy concentration for an alien substance of that kind. – The Year When Stardust Fell by Raymond F. Jones
  3. We hear frightful stories about this new concentration policy. – Rainbow's End by Rex Beach