fol·low·er 
(fŏlō-ər)
(fŏlō-ər)n.
1. One that follows, especially:
a. One who accepts the guidance, command, or leadership of another: a follower of Gandhi.
b. One who has a strong interest or pays close attention to something: a follower of new developments in technology.
2. A machine element moved by another machine element.