The Collaborative International Dictionary of English v.0.48:

Compasses \Com"pass*es\, n., pl.
   An instrument for describing circles, measuring figures,
   etc., consisting of two, or (rarely) more, pointed branches,
   or legs, usually joined at the top by a rivet on which they
   move.
   [1913 Webster]

   Note: The compasses for drawing circles have adjustable pen
         points, pencil points, etc.; those used for measuring
         without adjustable points are generally called
         dividers. See Dividers.
         [1913 Webster]

   Bow compasses. See Bow-compass.

   Caliber compasses, Caliper compasses. See Calipers.

   Proportional, Triangular, etc., compasses. See under
      Proportional, etc.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Proportional \Pro*por"tion*al\, n.
   1. (Math.) Any number or quantity in a proportion; as, a mean
      proportional.
      [1913 Webster]

   2. (Chem.) The combining weight or equivalent of an element.
      [Obs.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Proportional \Pro*por"tion*al\, a. [L. proportionalis: cf. F.
   proportionnel.]
   1. Having a due proportion, or comparative relation; being in
      suitable proportion or degree; as, the parts of an edifice
      are proportional. --Milton.
      [1913 Webster]

   2. Relating to, or securing, proportion. --Hutton.
      [1913 Webster]

   3. (Math.) Constituting a proportion; having the same, or a
      constant, ratio; as, proportional quantities; momentum is
      proportional to quantity of matter.
      [1913 Webster]

   Proportional logarithms, logistic logarithms. See under
      Logistic.

   Proportional scale, a scale on which are marked parts
      proportional to the logarithms of the natural numbers; a
      logarithmic scale.

   Proportional scales, compasses, dividers, etc.
      (Draughting), instruments used in making copies of
      drawings, or drawings of objects, on an enlarged or
      reduced scale.
      [1913 Webster]

WordNet (r) 3.0 (2006):

proportional
    adj 1: properly related in size or degree or other measurable
           characteristics; usually followed by `to'; "the
           punishment ought to be proportional to the crime";
           "earnings relative to production" [syn: proportional,
           relative]
    2: having a constant ratio
    n 1: one of the quantities in a mathematical proportion

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "proportional":
   3-D, affinitive, analogical, analogous, appertaining, associative,
   balanced, commensurable, commensurate, comparable, comparative,
   compatible, congenial, connective, consistent, contingent,
   correlated, correlative, corresponding, cubic, dependent,
   dimensional, distributional, distributive, en rapport, equal,
   even stephen, fifty-fifty, flat, fourth-dimensional, half,
   half-and-half, halvers, harmonious, in accordance with, linking,
   particular, per capita, per head, pertaining, pertinent, pro rata,
   proportionable, proportionate, proportioned, prorated, reciprocal,
   referable, referring, related, relating, relational, relative,
   respective, several, space, space-time, spatial, spatiotemporal,
   spherical, stereoscopic, superficial, surface, symmetrical,
   sympathetic, three-dimensional, two-dimensional, volumetric