From Longman Dictionary of Contemporary Englishtrackertrack‧er /ˈtrækə $ -ər/ noun [countable] someone who follows and finds other people, especially by following the marks that they have left on the ground
Examples from the Corpus
tracker• We both employed local Arussi as trackers, some of whom were very skilful and all of whom were tireless.• While they rested, Devraux again sent his trackers to climb lookout trees.• After a moment's hesitation Jacques Devraux followed at a distance with his trackers.• a financial investment tracker• Then, treading carefully, he followed on behind the last Moi trackers.• a star tracker• Even before the summit, the trackers announced they had located the gorillas and we should prepare to enter their presence.• Then Tagan, the tracker, stopped and stood in his stirrups, his head up and his eyes narrowed.• The eighth, a black-bearded, brown-faced man named Tagan was the tracker.• The tracker who had worked with Ian Hofmeyr darting the Deduru-Oya elephants was forced to guide the raiders out of the park. 