The Collaborative International Dictionary of English v.0.48:

Genealogy \Gen`e*al"o*gy\, n.; pl. Genealogies. [OE.
   genealogi, genelogie, OF. genelogie, F. g['e]n['e]alogie, L.
   genealogia, fr. Gr. ?; ? birth, race, descent (akin to L.
   genus) + ? discourse.]
   [1913 Webster]
   1. An account or history of the descent of a person or family
      from an ancestor; enumeration of ancestors and their
      children in the natural order of succession; a pedigree.
      [1913 Webster]

   2. Regular descent of a person or family from a progenitor;
      pedigree; lineage.
      [1913 Webster]

WordNet (r) 3.0 (2006):

genealogy
    n 1: successive generations of kin [syn: genealogy, family
         tree]
    2: the study or investigation of ancestry and family history

The Devil's Dictionary (1881-1906):

GENEALOGY, n.  An account of one's descent from an ancestor who did
not particularly care to trace his own.