The Collaborative International Dictionary of English v.0.48:

Metalepsis \Met`a*lep"sis\, n.; pl. Metalepses. [L., fr. Gr. ?
   participation, alteration, fr. ? to partake, to take in
   exchange; ? beyond + ? to take.] (Rhet.)
   The continuation of a trope in one word through a succession
   of significations, or the union of two or more tropes of a
   different kind in one word.
   [1913 Webster]

WordNet (r) 3.0 (2006):

metalepsis
    n 1: substituting metonymy of one figurative sense for another