There is much talk about leadership out there, and many different ways to define it. The best definition I've heard is one of the simplest:
Leadership is influence.
If you are not influencing anyone, regardless of what position or title you hold, you are not leading them. If you are influencing others, like it or not, you are leading. The level of your influence upon others, and what you are changing them towards, determines the effectiveness of your leadership. You may use that influence for good or evil, but either way you are leading.
This is true in the church, this is true in your home, and this is true in your business. Use your leadership wisely and to God's glory.