The Collaborative International Dictionary of English v.0.48:

Weight \Weight\, v. t. [imp. & p. p. Weighted; p. pr. & vb. n.
   Weighting.]
   [1913 Webster]
   1. To load with a weight or weights; to load down; to make
      heavy; to attach weights to; as, to weight a horse or a
      jockey at a race; to weight a whip handle.
      [1913 Webster]

            The arrows of satire, . . . weighted with sense.
                                                  --Coleridge.
      [1913 Webster]

   2. (Astron. & Physics) To assign a weight to; to express by a
      number the probable accuracy of, as an observation. See
      Weight of observations, under Weight.
      [1913 Webster]

   3. (Dyeing) To load (fabrics) as with barite, to increase the
      weight, etc.
      [Webster 1913 Suppl.]

   4. (Math.) to assign a numerical value expressing relative
      importance to (a measurement), to be multiplied by the
      value of the measurement in determining averages or other
      aggregate quantities; as, they weighted part one of the
      test twice as heavily as part 2.
      [PJC]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Weight \Weight\, n. [OE. weght, wight, AS. gewiht; akin to D.
   gewigt, G. gewicht, Icel. v[ae]tt, Sw. vigt, Dan. v[ae]gt.
   See Weigh, v. t.]
   [1913 Webster]
   1. The quality of being heavy; that property of bodies by
      which they tend toward the center of the earth; the effect
      of gravitative force, especially when expressed in certain
      units or standards, as pounds, grams, etc.
      [1913 Webster]

   Note: Weight differs from gravity in being the effect of
         gravity, or the downward pressure of a body under the
         influence of gravity; hence, it constitutes a measure
         of the force of gravity, and being the resultant of all
         the forces exerted by gravity upon the different
         particles of the body, it is proportional to the
         quantity of matter in the body.
         [1913 Webster]

   2. The quantity of heaviness; comparative tendency to the
      center of the earth; the quantity of matter as estimated
      by the balance, or expressed numerically with reference to
      some standard unit; as, a mass of stone having the weight
      of five hundred pounds.
      [1913 Webster]

            For sorrow, like a heavy-hanging bell,
            Once set on ringing, with his own weight goes.
                                                  --Shak.
      [1913 Webster]

   3. Hence, pressure; burden; as, the weight of care or
      business. "The weight of this said time." --Shak.
      [1913 Webster]

            For the public all this weight he bears. --Milton.
      [1913 Webster]

            [He] who singly bore the world's sad weight.
                                                  --Keble.
      [1913 Webster]

   4. Importance; power; influence; efficacy; consequence;
      moment; impressiveness; as, a consideration of vast
      weight.
      [1913 Webster]

            In such a point of weight, so near mine honor.
                                                  --Shak.
      [1913 Webster]

   5. A scale, or graduated standard, of heaviness; a mode of
      estimating weight; as, avoirdupois weight; troy weight;
      apothecaries' weight.
      [1913 Webster]

   6. A ponderous mass; something heavy; as, a clock weight; a
      paper weight.
      [1913 Webster]

            A man leapeth better with weights in his hands.
                                                  --Bacon.
      [1913 Webster]

   7. A definite mass of iron, lead, brass, or other metal, to
      be used for ascertaining the weight of other bodies; as,
      an ounce weight.
      [1913 Webster]

   8. (Mech.) The resistance against which a machine acts, as
      opposed to the power which moves it. [Obs.]
      [1913 Webster]

   Atomic weight. (Chem.) See under Atomic, and cf.
      Element.

   Dead weight, Feather weight, Heavy weight, Light
   weight, etc. See under Dead, Feather, etc.

   Weight of observation (Astron. & Physics), a number
      expressing the most probable relative value of each
      observation in determining the result of a series of
      observations of the same kind.
      [1913 Webster]

   Syn: Ponderousness; gravity; heaviness; pressure; burden;
        load; importance; power; influence; efficacy;
        consequence; moment; impressiveness.
        [1913 Webster]

WordNet (r) 3.0 (2006):

weight
    n 1: the vertical force exerted by a mass as a result of gravity
    2: sports equipment used in calisthenic exercises and
       weightlifting; it is not attached to anything and is raised
       and lowered by use of the hands and arms [syn: weight,
       free weight, exercising weight]
    3: the relative importance granted to something; "his opinion
       carries great weight"; "the progression implied an increasing
       weightiness of the items listed" [syn: weight,
       weightiness]
    4: an artifact that is heavy
    5: an oppressive feeling of heavy force; "bowed down by the
       weight of responsibility"
    6: a system of units used to express the weight of something
       [syn: system of weights, weight]
    7: a unit used to measure weight; "he placed two weights in the
       scale pan" [syn: weight unit, weight]
    8: (statistics) a coefficient assigned to elements of a
       frequency distribution in order to represent their relative
       importance [syn: weight, weighting]
    v 1: weight down with a load [syn: burden, burthen,
         weight, weight down] [ant: disburden, unburden]
    2: present with a bias; "He biased his presentation so as to
       please the share holders" [syn: slant, angle, weight]

Moby Thesaurus II by Grady Ward, 1.0:

341 Moby Thesaurus words for "weight":
   Indian club, accent, affliction, amperage, armipotence, ascendancy,
   authoritativeness, authority, balance, ballast, barbell, be heavy,
   beef, bitter cup, bitter draft, bitter draught, bitter pill,
   black power, bob, brim, brute force, buckram, burden,
   burden of care, burden with, burthen, cankerworm of care, carat,
   care, cargo, carry weight, centigram, ceremonial, ceremoniousness,
   ceremony, charge, charisma, charm, chock, clout, cogence, cogency,
   compulsion, concern, concernment, congest, consequence,
   consequentiality, consideration, contaminate, control, corrupt,
   counterbalance, cram, credit, cross, crowd, crown of thorns,
   cumber, cumbrance, curse, deadweight, debase, decagram, decigram,
   demand, difficulty, dignity, dint, disadvantage, distress, doctor,
   dominance, domination, dram, dram avoirdupois, drive, dumbbell,
   duress, duty, dyne, effect, effectiveness, effectuality, efficacy,
   embarrassment, eminence, emphasis, enchantment, encumber,
   encumbrance, energy, enjoin, esteem, exact, excellence, exerciser,
   extrinsicality, fasten upon, favor, fill, fill to overflowing,
   fill up, flower power, force, force majeure, forcefulness, form,
   formality, formalization, foul up, freight, freight with,
   full blast, full force, gall, gall and wormwood, good feeling,
   grain, gram, gravity, greatness, grievance, hamper, handicap,
   have weight, heft, high order, high rank, hold, hold the scales,
   horse, hundredweight, impediment, impedimenta, impersonality,
   import, importance, impose, impose on, impose upon, imposition,
   incidental power, inconvenience, inflict on, inflict upon,
   infliction, influence, influentiality, influentialness,
   insinuation, interest, jam, jam-pack, justness, kilo, kilogram,
   lade, lay, lay on, lead, leadership, leverage, levy, lie heavy,
   load, long horse, lumber, magnetism, magnitude, main force,
   main strength, mana, mark, mass, mastery, materiality, megaton,
   merit, might, might and main, mightiness, milligram, millstone,
   mole, moment, momentousness, moxie, muscle power, note, onus,
   oppression, ounce, ounce avoirdupois, ounce troy, overfill, pack,
   pack of troubles, pad, parallel bars, paramountcy,
   peck of troubles, penalty, pennyweight, personality, persuasion,
   pith, pizzazz, place, plumb, plummet, pomp, pomposity, poop,
   potence, potency, potentiality, pound, pound avoirdupois,
   pound troy, poundal, power, power pack, power structure,
   power struggle, powerfulness, precedence, predominance,
   preeminence, preponderance, prepotency, pressure, prestige,
   primacy, primness, priority, productiveness, productivity,
   prominence, puissance, pull, punch, punching bag, purchase, push,
   put, put down, put on, put upon, ram in, rank, reign, repute,
   rigidness, rings, ritual, rituality, rowing machine, rule, saddle,
   saddle with, sandbag, satiate, saturate, say, scruple,
   sea of troubles, self-importance, seniority, set, side horse,
   significance, signification, sinew, sinker, slug, solemnity,
   solidity, sophisticate, sorrow, soundness, spoil, starchiness,
   stature, steam, stiffness, stiltedness, stone, strength, stress,
   strike a balance, strong arm, stuff, stylization, suasion,
   subject to, substantiality, subtle influence, suggestion,
   supercharge, superiority, superpower, supremacy, surfeit, sway,
   task, tax, thorn, tip the scales, ton, top off, trampoline,
   trapeze, trouble, units of weight, upper hand, validity, value,
   vehemence, vigor, vim, virility, virtue, virulence, vitality, wad,
   waters of bitterness, wattage, weigh, weigh down, weigh heavy,
   weigh in, weigh out, weight down, weight down with, weightiness,
   whip hand, white elephant, woe, worth, yoke with



Bouvier's Law Dictionary, Revised 6th Ed (1856):

WEIGHT. A quality in natural bodies, by which they tend towards the centre
of the earth.
     2. Under the article Measure, (q.v.) it is said that by the
constitution congress possesses the power "to fix the standard of weights
and measures," and that this power has not been exercised.
     3. The weights now generally used in the United States, are the same as
those of England; they are of two kinds:

                 1. AVOIRDUPOIS WEIGHT.
  1st. Used in almost all commercial transactions, and in the common
dealings of life.
 27 1/3 1/2 grains  =    1 dram
 16 drams           =    1 ounce
 16 ounces          =    1 pound, (lb.)
 28 pounds          =    1 quarter, (qr.)
 4 quarters         =    1 hundred weight, (cwt.)
 20 hundred weight  =    1 ton.

 2d. Used for meat and fish.
 8 pounds           =    1 stone

 3d. Used in the wool trade.
                                     Cwt. qr.  lb.
 7 pounds           =    1 clove 14 pounds           =    1 stone  =   0
0   14
 2 stones           =    1 tod    =   0    1    0
 6 1/2 tods         =    1 wey    =   1    2   14
 2 weys             =    1 sack   =   3    1    0 12 sacks            =    1
last   =  39    0    0

 4th. Used for butter and cheese.
 8 pounds           =    1 clove
 56 pounds          =    1 firkin.

                     2. TROY WEIGHT.
 24 grams           =    1 pennyweight
 20 pennyweights    =    1 ounce
 12 ounces          =    1 pound.

     4. These are the denominations of troy weight, when used for weighing
gold, silver and precious stones, except diamonds. Troy weight is also used
by apothecaries in compounding medicines; and by them the ounce is divided
into eight drams, and the drain into three scruples, so that the latter is
equal to twenty grains. For scientific purposes, the grain only is used, and
sets of weights are constructed in decimal progression, from 10,000 grains
downward to one-hundredth of a grain. The caret, used for weighing diamonds,
is three and one-sixth grains.
     5. A short account of the French weights and measures is given under
the article Measure.