The Dock 
  
  The Dock is a place to store applications that you want to be ready at hand.  

  ￼

  Applications you start will also be visible at the Dock. Started applications will not have the ’...’ marker, while the not started applications have the ’...’ marker.
  To make an application the active one you can double click its icon on the Dock. Hidden application are shown on the Dock with a single ’.’ in their icon. By double clicking this icon the application gets unhidden and becobes the active one.

   ￼