com·pac·tion /kəmˈpækʃən, kɑm-/
  緊湊
  compaction
  簡縮
  compaction
  緊密 壓緊
  Com·pac·tion n.  The act of making compact, or the state of being compact. [Obs.]
  ◄ ►
  compaction
       n 1: an increase in the density of something [syn: compression,
             concretion, densification]
       2: the act of crushing [syn: crush, crunch]