A term originally refering to the followers of Christ Jesus. They were frequently refered to as the brothers. Just as your "brothers" are your posse and are always near you, so also Jesus' posse was always with him--learning and growing from what he had to say.
Now, the term can refer to anyone who follows the teachings of another. It is a word that combines the definitions of student and follower.
Recipe for a Disciple-
"Rejoice in the Lord always. I will say it again: Rejoice! Let your gentleness be evident to all. The Lord is near. Do not be anxious about anything, but in everything, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus."
"Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things. Whatever you have learned or received or heard from me, or seen in me—put it into practice. And the God of peace will be with you."