The Collaborative International Dictionary of English v.0.48:

Teleology \Te`le*ol"o*gy\, n. [Gr. ?, teleos, the end or issue +
   -logy: cf. F. t['e]l['e]ologie.]
   The doctrine of the final causes of things; specif. (Biol.),
   the doctrine of design, which assumes that the phenomena of
   organic life, particularly those of evolution, are explicable
   only by purposive causes, and that they in no way admit of a
   mechanical explanation or one based entirely on biological
   science; the doctrine of adaptation to purpose.
   [1913 Webster]

WordNet (r) 3.0 (2006):

teleology
    n 1: (philosophy) a doctrine explaining phenomena by their ends
         or purposes