The Collaborative International Dictionary of English v.0.48:

Truss \Truss\, n. [OE. trusse, F. trousse, OF. also tourse;
   perhaps fr. L. tryrsus stalk, stem. Cf. Thyrsus, Torso,
   Trousers, Trousseau.]
   1. A bundle; a package; as, a truss of grass. --Fabyan.
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            Bearing a truss of trifles at his back. --Spenser.
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   Note: A truss of hay in England is 56 lbs. of old and 60 lbs.
         of new hay; a truss of straw is 36 lbs.
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   2. A padded jacket or dress worn under armor, to protect the
      body from the effects of friction; also, a part of a
      woman's dress; a stomacher. [Obs.] --Nares.
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            Puts off his palmer's weed unto his truss, which
            bore
            The stains of ancient arms.           --Drayton.
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   3. (Surg.) A bandage or apparatus used in cases of hernia, to
      keep up the reduced parts and hinder further protrusion,
      and for other purposes.
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   4. (Bot.) A tuft of flowers formed at the top of the main
      stalk, or stem, of certain plants.
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   5. (Naut.) The rope or iron used to keep the center of a yard
      to the mast.
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   6. (Arch. & Engin.) An assemblage of members of wood or
      metal, supported at two points, and arranged to transmit
      pressure vertically to those points, with the least
      possible strain across the length of any member.
      Architectural trusses when left visible, as in open timber
      roofs, often contain members not needed for construction,
      or are built with greater massiveness than is requisite,
      or are composed in unscientific ways in accordance with
      the exigencies of style.
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   Truss rod, a rod which forms the tension member of a
      trussed beam, or a tie rod in a truss.
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