contact inhibition

1. The inhibition of continued growth and division of a cell or colony due to physical contact with other cells or colonies. The stopping of continued growth when a certain density of cells has been reached.
   
   
2. The momentary stopping of all movement when a mobile cell runs into another cell.

From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.