Definition from Wiktionary, the free dictionary
Alternative forms 
- side-track, side track
sidetrack (plural sidetracks)
- (rail transport) A second, relatively short length of track just to the side of a railroad track, joined to the main track by switches at one or both ends, used either for unloading freight, or to allow two trains on a same track to meet (opposite directions) or pass (same direction); a railroad siding.
- (sometimes) Any auxiliary railroad track, as differentiated from a siding, that runs adjacent to the main track.
- (mining) A smaller tunnel or well drilled as an auxiliary off a main tunnel or well.
- An alternate train of thought, issue, topic, or activity, that is a deviation or distraction from the topic at hand or central activity, and secondary or subordinate in importance or effectiveness.
- Stay focused on the story; you keep getting lost in all of these little sidetracks.
- To divert (a locomotive) on to a lesser used track in order to allow other trains to pass.
- To divert or distract (someone) from a main issue or course of action with an alternate or less relevant topic or activity; or, to use deliberate trickery or sly wordplay when talking to (a person) in order to avoid discussion of a subject.
- Sorry I'm late. I got sidetracked with contributing to Wiktionary.
- The politician sidetracked the reporter with a story about duck hunting instead of a direct response to the question that was asked.
- I hope you can sidetrack the teacher with questions so we don't have to take the exam.
- To sideline; to push aside; to divert or distract from, reducing (something) to a secondary or subordinate position.
- The project was sidetracked in favor of a more popular program.
- He has sidetracked this debate for far too long.
- (intransitive) To deviate briefly from the topic at hand.
- Just to sidetrack a little bit from the subject I will explain my reasoning.
- To sidetrack for a moment, let me commend this team for their outstanding efforts.
- (deviate from the topic at hand): digress