1. in. [for a laser beam, a phonograph stylus, a tape head, etc.] to successfully transfer information to or from a recording medium. Something here won’t track. Must be the stylus.
2. in. [for a person] to make sense. (Usually in the negative.) She wasn’t tracking. There was no sense in trying to talk to her before she came out of it.
3. in. to coincide; to agree; to jibe. These two things don’t track. I don’t know what’s wrong.
4. n. a musical selection on a recording of some kind. The next track is my favorite.