The Collaborative International Dictionary of English v.0.48:

concentrated \concentrated\ adj.
   1. Having a high density of (the indicated substance); as, a
      narrow thread of concentrated ore.

   Note: [Narrower terms: undiluted (vs. diluted)]
         [WordNet 1.5]

   2. Gathered together or made less diffuse; as, their
      concentrated efforts; his concentrated attention. Opposite
      of distributed or diffused.

   Note: [Narrower terms: bunched, bunchy, clustered;
         centered, centred, centralized, focused;
         undivided] [Also See: compact.]
         [WordNet 1.5]

   3. Intense; in an extreme degree; -- of mental phenomena; as,
      her concentrated passion held them at bay.
      [WordNet 1.5]

   4. being the most concentrated solution possible at a given
      temperature; unable to dissolve still more of a substance.
      Opposite of dilute or unsaturated.

   Note: [Narrower terms: supersaturated]

   Syn: saturated.
        [WordNet 1.5]

   5. reduced to a stronger or more concentrated form; as,
      concentrated sulfuric acid. Opposite of diluted.

   Syn: condensed.
        [WordNet 1.5]

   6. characterized by intensity; especially when imposed from
      without; -- of actions; as, concentrated study.

   Syn: intensive.
        [WordNet 1.5]

   7. characterized by mental concentration.

   Syn: intent.
        [WordNet 1.5 +PJC]

The Collaborative International Dictionary of English v.0.48:

Center \Cen"ter\, Centre \Cen"tre\ v. i. [imp. & p. p.
   Centered or Centred (s[e^]n"t[~e]rd); p. pr. & vb. n.
   Centering or Centring.]
   1. To be placed in a center; to be central.
      [1913 Webster]

   2. To be collected to a point; to be concentrated; to rest
      on, or gather about, as a center.
      [1913 Webster]

            Where there is no visible truth wherein to center,
            error is as wide as men's fancies.    --Dr. H. More.
      [1913 Webster]

            Our hopes must center in ourselves alone. --Dryden.
      [1913 Webster] Center

The Collaborative International Dictionary of English v.0.48:

centered \centered\ (s[e^]n"t[~e]rd) adj.
   1. being or placed in the center.
      [WordNet 1.5]

   2. concentrated on or clustered around a central point or
      purpose.

   Syn: centred, centralized, focused.
        [WordNet 1.5] center field

WordNet (r) 3.0 (2006):

centered
    adj 1: being or placed in the center