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:

Center \Cen"ter\, Centre \Cen"tre\, v. t.
   1. To place or fix in the center or on a central point.
      --Milton.
      [1913 Webster]

   2. To collect to a point; to concentrate.
      [1913 Webster]

            Thy joys are centered all in me alone. --Prior.
      [1913 Webster]

   3. (Mech.) To form a recess or indentation for the reception
      of a center.
      [1913 Webster] Centerbit

The Collaborative International Dictionary of English v.0.48:

centre \cen"tre\, n. & v.
   See Center. [chiefly British]
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

Centre
    n 1: a low-lying region in central France
    2: an area that is approximately central within some larger
       region; "it is in the center of town"; "they ran forward into
       the heart of the struggle"; "they were in the eye of the
       storm" [syn: center, centre, middle, heart, eye]
    3: a point equidistant from the ends of a line or the
       extremities of a figure [syn: center, centre, midpoint]
    4: a place where some particular activity is concentrated; "they
       received messages from several centers" [syn: center,
       centre]
    5: the sweet central portion of a piece of candy that is
       enclosed in chocolate or some other covering [syn: center,
       centre]
    6: the choicest or most essential or most vital part of some
       idea or experience; "the gist of the prosecutor's argument";
       "the heart and soul of the Republican Party"; "the nub of the
       story" [syn: kernel, substance, core, center,
       centre, essence, gist, heart, heart and soul,
       inwardness, marrow, meat, nub, pith, sum, nitty-
       gritty]
    7: the object upon which interest and attention focuses; "his
       stories made him the center of the party" [syn: center,
       centre, center of attention, centre of attention]
    8: a cluster of nerve cells governing a specific bodily process;
       "in most people the speech center is in the left hemisphere"
       [syn: center, centre, nerve center, nerve centre]
    9: a building dedicated to a particular activity; "they were
       raising money to build a new center for research" [syn:
       center, centre]
    v 1: move into the center; "That vase in the picture is not
         centered" [syn: center, centre]
    2: direct one's attention on something; "Please focus on your
       studies and not on your hobbies" [syn: concentrate,
       focus, center, centre, pore, rivet]