To actively keep an account of something so that one is well informed about it, often with routinely monitoring or assessing it. You have so many students. I really wonder how you keep track of them all. Please keep track of these shipments so that we know if everything arrived. Movies these days have so many sequels that it's hard to keep track.
(of someone or something) Go to keep tab(s) (on someone or something).
lose track (of someone or something)
to lose contact with someone; to forget where something is. I lost track of all my friends from high school. Tom has lost track of his glasses again.
Remain informed, follow the course of, as in Are you keeping track of the time? This usage alludes to following a literal track, as of footsteps. The antonym, lose track, alludes to straying or wandering from a track, as in I've lost track-what day are you leaving? [Late 1800s]
see under keep track.