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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