Working in corporate America I had many bosses, some good and some not. However, I worked for just a handful of leaders.
A leader is someone who talks the talk and walks the walk. A leader will literally lead troops into battle. A business leader is someone who does the right thing no matter what the circumstances. A leader trusts employees and gives them autonomy and help as needed.
A leader learns new information and changes to address new realities and teaches staff to do the same.
A boss, on the other hand, closes his eyes and gets the work done by delegating some of the work to you. Growth and the advancement of himself and his team is not the main focus.