Tracker

Noun

1. Agent noun of track; one who, or that which, tracks or pursues, as a man or dog that follows game. A person employed to follow and monitor a political rival.
2. A person employed to follow and monitor a political rival.
3. In an organ, a light strip of wood connecting (in path) a key and a pallet, to communicate motion by pulling.
4. A type of computer software for composing music by aligning notes or samples on parallel timelines.
5. A musician who writes music in a tracker.