Declaration. 

abstract interface aParentInterface
{
  attribute string aStringAttribute;
  short aMethod (in long aLongArgument, inout float aFloatArgument);
}

interface aChildInterface : aParentInterface
{
  readonly attribute short aShortAttribute;
  oneway void aOnewayMethod (in long anArgument);
  void aTwowayMethod () raises anException;
}

Keywords.