The Collaborative International Dictionary of English v.0.48:

pathology \pa*thol"o*gy\ (-j[y^]), n.; pl. pathologies
   (-j[i^]z). [Gr. pa`qos a suffering, disease + -logy: cf. F.
   pathologie.]
   1. (Med.) The science which treats of diseases, their nature,
      causes, progress, symptoms, etc.
      [1913 Webster]

   Note: Pathology is general or special, according as it treats
         of disease or morbid processes in general, or of
         particular diseases; it is also subdivided into
         internal and external, or medical and surgical
         pathology. Its departments are nosology,
         [ae]tiology, morbid anatomy, symptomatology, and
         therapeutics, which treat respectively of the
         classification, causation, organic changes, symptoms,
         and cure of diseases.
         [1913 Webster]

   2. (Med.) The condition of an organ, tissue, or fluid
      produced by disease.
      [Webster 1913 Suppl.]

   Celluar pathology, a theory that gives prominence to the
      vital action of cells in the healthy and diseased
      functions of the body. --Virchow.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pathology
    n 1: the branch of medical science that studies the causes and
         nature and effects of diseases
    2: any deviation from a healthy or normal condition

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "pathology":
   abnormality, acute disease, affection, affliction, ailment,
   allergic disease, allergy, atrophy, bacterial disease,
   birth defect, blight, cardiovascular disease, chronic disease,
   circulatory disease, complaint, complication, condition,
   congenital defect, defect, deficiency disease, deformity,
   degenerative disease, disability, disease, disorder, distemper,
   endemic, endemic disease, endocrine disease, epidemic disease,
   functional disease, fungus disease, gastrointestinal disease,
   genetic disease, handicap, hereditary disease, iatrogenic disease,
   illness, indisposition, infectious disease, infirmity, malady,
   malaise, morbidity, morbus, muscular disease, neurological disease,
   nutritional disease, occupational disease, organic disease,
   pandemic disease, pathological condition, plant disease,
   protozoan disease, psychosomatic disease, respiratory disease,
   rockiness, secondary disease, seediness, sickishness, sickness,
   signs, symptomatology, symptomology, symptoms, syndrome, the pip,
   urogenital disease, virus disease, wasting disease, worm disease



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PATHOLOGY, med. jur. The science or doctrine of diseases. In cases of
homicides, abortions, and the like, it is of great consequence to the legal
practitioner to be acquainted, in some degree, with pathology. 2 Chit. Pr.
42, note.