co•a•lesce
  Pronunciation: (kō"u-les'), [key]    — v., -lesced, -lesc•ing. 
  
  
 —v.i.  - to grow together or into one body: The two lakes coalesced into one. 
  - to unite so as to form one mass, community, etc.: The various groups coalesced into a crowd. 
  - to blend or come together: Their ideas coalesced into one theory. 
  
  
 —v.t.  - to cause to unite in one body or mass.  
  
  
  Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.