Originally derived from the Medieval Latin word, fīliātiō (from fīlius, son), filiation literally means paternity, descent-fromfather,or line of descent. Concerning medicine, however, it refers to the connection of things resulting from one another,or contact tracing. The core idea behind filiation as a measure of precaution against outbreaks is to prevent the disease byinterrupting the chain of transmission with a systematical tracing and isolation of susceptible individuals having contact withany confirmed cases. Filiation became a widely used medical term in the first quarter of the 19th century, primarily in Frenchmedical literature, soon adapted to English and some other languages. In the Ottoman Empire, it appeared in medicaljournals in the 1850s, used primarily by some European physicians practicing in the country. As part of various measuresthat have been taken to tackle the current pandemic of COVID-19, the method of filiation was also recalled by the medicalcommunity. Soon after the observance of the first confirmed case of COVID-19 in Turkey on March 11, 2020, the indexcase and its contacts were identified and the Turkish Ministry of Health launched the procedures of filiation at a national levelwith ad-hoc medical teams established around the country. Aiming to shed light on the etymological and historical aspects offiliation, the current review discusses the concept based on original resources.