The Collaborative International Dictionary of English v.0.48:

Circumscribe \Cir`cum*scribe"\, v. t. [imp. & p. p.
   Circumscribed; p. pr. & vb. n. Circumscribing.] [L.
   circumscribere, -scriptum; circum + scribere to write, draw.
   See Soribe.]
   [1913 Webster]
   1. to write or engrave around. [R.]
      [1913 Webster]

            Thereon is circumscribed this epitaph. --Ashmole.
      [1913 Webster]

   2. To inclose within a certain limit; to hem in; to surround;
      to bound; to confine; to restrain.
      [1913 Webster]

            To circumscribe royal power.          --Bancroft.
      [1913 Webster]

   3. (Geom.) To draw a line around so as to touch at certain
      points without cutting. See Inscribe, 5.

   Syn: To bound; limit; restrict; confine; abridge; restrain;
        environ; encircle; inclose; encompass.
        [1913 Webster]

WordNet (r) 3.0 (2006):

circumscribe
    v 1: draw a line around; "He drew a circle around the points"
    2: restrict or confine, "I limit you to two visits to the pub a
       day" [syn: limit, circumscribe, confine]
    3: to draw a geometric figure around another figure so that the
       two are in contact but do not intersect

Moby Thesaurus II by Grady Ward, 1.0:

87 Moby Thesaurus words for "circumscribe":
   abate, abbreviate, adjust to, alter, assuage, bar, bound, box,
   box in, box up, circle in, coarct, compact, compress, concentrate,
   condense, condition, confine, consolidate, constrict, constringe,
   contract, cramp, curtail, decrease, define, delimit, delimitate,
   demarcate, determine, diminish, divide, draw, draw in,
   draw together, enclose, fetter, fix, hamper, hedge, hedge about,
   hem, hem in, keep from spreading, keep within bounds, knit,
   lay off, leaven, limit, localize, mark boundaries, mark off,
   mark out, mark the periphery, mitigate, moderate, modify, modulate,
   narrow, palliate, pucker, pucker up, purse, qualify, reduce,
   regulate by, restrain, restrict, rope off, season, separate,
   set conditions, set limits, set the limit, shorten, soften,
   solidify, specify, stake out, stint, strangle, strangulate,
   surround, temper, tighten, trammel, wrinkle