The Collaborative International Dictionary of English v.0.48:

Homogeneity \Ho`mo*ge*ne"i*ty\, n. [Cf. F.
   homog['e]n['e]it['e].]
   Same as Homogeneousness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

homogeneity
    n 1: the quality of being similar or comparable in kind or
         nature; "there is a remarkable homogeneity between the two
         companies" [syn: homogeneity, homogeneousness] [ant:
         heterogeneity, heterogeneousness]
    2: the quality of being of uniform throughout in composition or
       structure

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "homogeneity":
   accordance, agreement, calm, coequality, coincidence, congruence,
   consistency, consonance, constancy, continuity, correspondence,
   elementarity, equability, equality, equanimity, equilibrium,
   equivalence, evenness, fundamentality, homoousia, identity,
   indistinguishability, integrity, monism, monolithism,
   no difference, oneness, persistence, plainness, purity, sameness,
   self-identity, selfhood, selfness, selfsameness, severity,
   simpleness, simplicity, singleness, stability, starkness,
   steadfastness, steadiness, synonymity, synonymousness, synonymy,
   unadulteration, uniformity, unity, unmixedness, unruffledness,
   unsophistication