The document discusses several common idioms related to the word "track". It defines idioms such as "to track something down" meaning to search until finding something, "to backtrack" meaning to change an opinion or position, and "to be on the right track" meaning pursuing the correct approach. Other idioms covered include "to keep track of" meaning to monitor progress, "to lose track of" meaning to lose contact or forget, and "to cover one's tracks" meaning to conceal one's actions.