noun (n)

• (physics) a brief event in which two or more bodies come together(noun.event)

  Example:
  The collision of the particles resulted in an exchange of energy and a change of direction.
  

  Synonym:
  hit
  

  source: wordnet30
• an accident resulting from violent impact of a moving object(noun.event)

  Example:
  Three passengers were killed in the collision.
  The collision of the two ships resulted in a serious oil spill.
  

  source: wordnet30
• a conflict of opposed ideas or attitudes or goals(noun.communication)

  Example:
  A collision of interests.
  

  source: wordnet30
• The act of striking together; a striking together, as of two hard bodies; a violent meeting, as of railroad trains; a clashing.(noun)

  source: webster1913