The Collaborative International Dictionary of English v.0.48:

Abscission \Ab*scis"sion\, n. [L. abscissio. See Abscind.]
   1. The act or process of cutting off. "Not to be cured
      without the abscission of a member." --Jer. Taylor.
      [1913 Webster]

   2. The state of being cut off. --Sir T. Browne.
      [1913 Webster]

   3. (Rhet.) A figure of speech employed when a speaker having
      begun to say a thing stops abruptly: thus, "He is a man of
      so much honor and candor, and of such generosity -- but I
      need say no more."
      [1913 Webster]

WordNet (r) 3.0 (2006):

abscission
    n 1: shedding of flowers and leaves and fruit following
         formation of scar tissue in a plant
    2: the act of cutting something off [syn: abscission, cutting
       off]