Kalin is of Bulgarian origin, derived from the Slavic element 'kalina', meaning 'permanent'. It gained popularity as a given name in Bulgaria and other Slavic countries during the 20th century.
The name Kalin experienced significant fluctuations in popularity over the years, with peaks in the late 1980s and early to mid-1990s, and a gradual decline thereafter, reaching an all-time low in recent years.