The Collaborative International Dictionary of English v.0.48:

Ablactation \Ab`lac*ta"tion\ n.
   1. The weaning of a child from the breast, or of young beasts
      from their dam. --Blount.
      [1913 Webster]

   2. (Hort.) The process of grafting now called inarching, or
      grafting by approach.
      [1913 Webster]