The Collaborative International Dictionary of English v.0.48:

Poise \Poise\, n. [OE. pois, peis, OF. pois, peis, F. poids, fr.
   L. pensum a portion weighed out, pendere to weigh, weigh out.
   Cf. Avoirdupois, Pendant, Poise, v.] [Formerly written
   also peise.]
   1. Weight; gravity; that which causes a body to descend;
      heaviness. "Weights of an extraordinary poise." --Evelyn.
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   2. The weight, or mass of metal, used in weighing, to balance
      the substance weighed.
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   3. The state of being balanced by equal weight or power;
      equipoise; balance; equilibrium; rest. --Bentley.
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   4. That which causes a balance; a counterweight.
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            Men of unbounded imagination often want the poise of
            judgment.                             --Dryden.
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   5. a dignified and self-confident manner; graceful composure
      and tact in handling difficult social situations.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Poise \Poise\, v. i.
   To hang in equilibrium; to be balanced or suspended; hence,
   to be in suspense or doubt.
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         The slender, graceful spars
         Poise aloft in air.                      --Longfellow.
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The Collaborative International Dictionary of English v.0.48:

Poise \Poise\, v. t. [imp. & p. p. Poised, ; p. pr. & vb. n.
   Poising.] [OE. poisen, peisen, OF. & F. peser, to weigh,
   balance, OF. il peise, il poise, he weighs, F. il p[`e]se,
   fr. L. pensare, v. intens. fr. pendere to weigh. See Poise,
   n., and cf. Pensive.] [Formerly written also peise.]
   1. To balance; to make of equal weight; as, to poise the
      scales of a balance.
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   2. To hold or place in equilibrium or equiponderance.
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            Nor yet was earth suspended in the sky;
            Nor poised, did on her own foundation lie. --Dryden.
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   3. To counterpoise; to counterbalance.
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            One scale of reason to poise another of sensuality.
                                                  --Shak.
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            To poise with solid sense a sprightly wit. --Dryden.
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   4. To ascertain, as by the balance; to weigh.
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            He can not sincerely consider the strength, poise
            the weight, and discern the evidence. --South.
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   5. To weigh (down); to oppress. [Obs.]
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            Lest leaden slumber peise me down to-morrow. --Shak.
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WordNet (r) 3.0 (2006):

poise
    n 1: a cgs unit of dynamic viscosity equal to one dyne-second
         per square centimeter; the viscosity of a fluid in which a
         force of one dyne per square centimeter maintains a
         velocity of 1 centimeter per second
    2: a state of being balanced in a stable equilibrium
    3: great coolness and composure under strain; "keep your cool"
       [syn: aplomb, assuredness, cool, poise, sang-froid]
    v 1: be motionless, in suspension; "The bird poised for a few
         moments before it attacked"
    2: prepare (oneself) for something unpleasant or difficult [syn:
       brace, poise]
    3: cause to be balanced or suspended
    4: hold or carry in equilibrium [syn: poise, balance]