The Collaborative International Dictionary of English v.0.48:

Subdivision \Sub`di*vi"sion\, n. [L. subdivisio: cf. F.
   subdivision.]
   1. The act of subdividing, or separating a part into smaller
      parts.
      [1913 Webster]

   2. A part of a thing made by subdividing.
      [1913 Webster]

            In the decimal table, the subdivision of the cubit,
            as span, palm, and digit, are deduced from the
            shorter cubit.                        --Arbuthnot.
      [1913 Webster]

WordNet (r) 3.0 (2006):

subdivision
    n 1: an area composed of subdivided lots
    2: the act of subdividing; division of something previously
       divided
    3: a division of some larger or more complex organization; "a
       branch of Congress"; "botany is a branch of biology"; "the
       Germanic branch of Indo-European languages" [syn: branch,
       subdivision, arm]
    4: a self-contained part of a larger composition (written or
       musical); "he always turns first to the business section";
       "the history of this work is discussed in the next section"
       [syn: section, subdivision]
    5: a section of a section; a part of a part; i.e., a part of
       something already divided [syn: subsection, subdivision]

Moby Thesaurus II by Grady Ward, 1.0:

170 Moby Thesaurus words for "subdivision":
   abstraction, adjunct, alienation, analysis, analyzation,
   anatomizing, anatomy, arrangement, assay, assaying,
   assembly-line housing, bifidity, bifurcation, billeting,
   bipartition, bisection, blood, bracket, branch, branching,
   breakdown, breaking down, breaking up, breakup, by two, caste,
   cataloging, categorization, category, census, clan, class,
   classification, codification, component, composition, constituents,
   content, contents, contingent, cross section, cutting in two,
   detachment, detail, dichotomy, dimidiation, disarticulation,
   disassociation, disconnectedness, disconnection, discontinuity,
   disengagement, disjointing, disjunction, dislocation, dissection,
   disunion, division, divisions, divorce, divorcement, docimasy,
   dole, domiciliation, doss, elements, estate, filing, forking,
   fraction, grade, grading, gravimetric analysis, group, grouping,
   guts, halving, head, heading, hospitality, housing, housing bill,
   housing development, housing problem, in half, incoherence, index,
   indexing, ingredients, innards, insides, installment, inventory,
   isolation, item, items, kin, label, level, list, living quarters,
   lodging, lodgment, lower-income housing, luxation, order, parcel,
   part, particular, parting, partition, parts, percentage,
   pigeonhole, pigeonholing, placement, portion, position,
   predicament, proximate analysis, quadrant, quantitative analysis,
   quarter, quartering, quota, race, ramification, random sample,
   ranging, rank, ranking, rating, reduction to elements, remainder,
   removal, resolution, rubric, sample, sampling, section, sector,
   segment, segmentation, semimicroanalysis, separation, separatism,
   sept, set, share, slum clearance, sorting, station, status, strain,
   stratification, stratum, subgroup, suborder, subspecies,
   subtraction, tabulation, taxonomy, title, tract, transient lodging,
   typology, urban renewal, whole, withdrawal, zoning