Dan Allender gives a great definition of a leader in his book Leading with a Limp.
“A leader is anyone who has someone following her. If anyone looks to you for wisdom, counsel, or direction, then you are a leader. If there is one little girl who looks at you and says, “Mommy,” then you are a leader. If there are fourteen high-energy boys holding aluminum weapons and screaming that they want to be first to hit the ball that rests on a rubber T-ball frame, then you are a leader.
It takes only one child grabbing your finger with a small, sometimes-trembling hand to signify that you are a leader. And from your child’s birth to the day you pass from this earth, you will continue to make life-shaping decisions as a parent. And of course it’s not just parents who lead with such power and influence. Anyone who wrestles with an uncertain future on behalf of others— anyone who uses her gifts, talents, and skills to influence the direction of others for the greater good— is a leader.
No one is a mere follower. If you are a follower of God, for instance, then you are called to lead. Every believer is called to help someone grow into maturity— and such is the core calling of a leader.”