The Collaborative International Dictionary of English v.0.48:

Structure \Struc"ture\, n. [L. structura, from struere,
   structum, to arrange, build, construct; perhaps akin to E.
   strew: cf. F. structure. Cf. Construe, Destroy,
   Instrument, Obstruct.]
   1. The act of building; the practice of erecting buildings;
      construction. [R.]
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            His son builds on, and never is content
            Till the last farthing is in structure spent. --J.
                                                  Dryden, Jr.
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   2. Manner of building; form; make; construction.
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            Want of insight into the structure and constitution
            of the terraqueous globe.             --Woodward.
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   3. Arrangement of parts, of organs, or of constituent
      particles, in a substance or body; as, the structure of a
      rock or a mineral; the structure of a sentence.
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            It [basalt] has often a prismatic structure. --Dana.
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   4. (Biol.) Manner of organization; the arrangement of the
      different tissues or parts of animal and vegetable
      organisms; as, organic structure, or the structure of
      animals and plants; cellular structure.
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   5. That which is built; a building; esp., a building of some
      size or magnificence; an edifice.
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            There stands a structure of majestic frame. --Pope.
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   Columnar structure. See under Columnar.
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WordNet (r) 3.0 (2006):

structure
    n 1: a thing constructed; a complex entity constructed of many
         parts; "the structure consisted of a series of arches";
         "she wore her hair in an amazing construction of whirls and
         ribbons" [syn: structure, construction]
    2: the manner of construction of something and the arrangement
       of its parts; "artists must study the structure of the human
       body"; "the structure of the benzene molecule"
    3: the complex composition of knowledge as elements and their
       combinations; "his lectures have no structure"
    4: a particular complex anatomical part of a living thing; "he
       has good bone structure" [syn: structure, anatomical
       structure, complex body part, bodily structure, body
       structure]
    5: the people in a society considered as a system organized by a
       characteristic pattern of relationships; "the social
       organization of England and America is very different";
       "sociologists have studied the changing structure of the
       family" [syn: social organization, social organisation,
       social structure, social system, structure]
    v 1: give a structure to; "I need to structure my days"

Moby Thesaurus II by Grady Ward, 1.0:

301 Moby Thesaurus words for "structure":
   Dymaxion house, IC analysis, Platonic form, Platonic idea,
   White House, action, adobe house, aesthetic form, anagnorisis,
   anatomy, angle, appositive, archetype, architectonics,
   architecture, argument, arrange, arrangement, array, art form,
   assemblage, assemble, assembly, atmosphere, attribute, attributive,
   background, build, build up, building, buildup, casa, cast,
   catastrophe, character, characterization, clarity, clear-cutness,
   clearness, cliff dwelling, coherence, color, combination, combine,
   complement, complex, complication, compose, composition, compound,
   concord, configuration, conformation, connectedness, consist of,
   consistency, constitute, constitution, construct, construction,
   construction modifier, consulate, continuity, contrivance,
   cool off, country house, country seat, crystallinity, cut, cutting,
   dacha, deanery, deep structure, definition, denouement, deploy,
   deployment, design, development, device, direct object, directness,
   disposal, dispose, disposition, distinctness, dwelling house,
   edifice, embassy, embodiment, embody, enter into, episode,
   erection, establishment, explicitness, fable, fabric, fabricate,
   fabrication, falling action, farm, farmhouse, fashion, fashioning,
   feel, figuration, figure, filler, finish, form, form-function unit,
   format, formation, frame, framework, function, genre, getup,
   gimmick, go into, grade, grain, granular texture, hall, harmonize,
   harmony, hierarchize, house, houseboat,
   immediate constituent analysis, impression, incident, incorporate,
   incorporation, indentation, indirect object, inner form, join,
   junction, knub, lake dwelling, lay out, layout, levels, limpidity,
   line, line up, lineup, living machine, local color, lodge,
   lucidity, make, make up, makeup, manor house, manse, marshal,
   marshaling, matrix, merge in, methodize, mix, mixture, modality,
   mode, model, modifier, mold, mood, morphology, motif, movement,
   mythos, nap, nature, network, normalize, nub, object, order,
   organization, organize, pacify, packaged house, parsonage, pattern,
   peace, pellucidity, penthouse, peripeteia, perspicuity,
   phrase structure, piece together, piecing together, pile, pit,
   plain English, plain speech, plain style, plainness, plan, plot,
   pock, predicate, prefab, prefabricated house, prefabrication,
   presidential palace, proportion, prototype, protuberance,
   put together, putting together, pyramid, qualifier, quiet,
   quietude, ranch house, rank, ranks, recognition, rectory,
   regularity, regularize, regulate, rising action, roof, routine,
   routinize, scheme, secondary plot, set, set up, setup, shag,
   shallow structure, shape, shaping, significant form, simplicity,
   skeleton, skyscraper, slant, slot, slot and filler, sod house,
   split-level, stamp, standardize, story, straightforwardness,
   strata, structuring, style, subject, subplot, superstructure,
   surface, surface structure, surface texture, switch, symmetry,
   syneresis, syntactic analysis, syntactic structure, syntactics,
   syntax, synthesis, synthesize, system, systematize, tagmeme,
   texture, thematic development, theme, tone, topic, tower,
   town house, tranquilize, tranquillity, transparency, transpicuity,
   turn, twist, type, unadorned style, unambiguousness,
   underlying structure, unequivocalness, uniformity, unite in,
   unmistakableness, vicarage, wale, weave, woof, word arrangement,
   word order