What does Finnian mean?
Anglicized form of Gaelic FinnÚn, derived from finn. Also used as pet form of Finn. The 1968 film "Finian's Rainbow" was Fred Astaire's last musical. The name of several early saints, one of whom may have been the same person as Saint Finbar. Saint Finnian of Clonard (sixth century) was called "The Teacher of Irish Saints" because many students at his school became prominent ecclesiastics.
How popular is Finnian?
Finnian is an uncommonly occurring first name for men. Finnian is also an uncommon surname for all people. (2000 U.S. Census)
Below is a charted comparison of the usage of the boy name Finnian and corresponding names. Barry, Finn (#234 2 years ago) and Fionn are the prominent variation forms of Finnian (outside Top 1000). These forms of Finnian reached the peak of their popularity during the years 1950-1959 (average #691) and are almost as popular today (#744, ▼17.2%), but with the version Barry becoming less fashionable. Barry is more familiar than the rest, although Finn appears to be gaining favor too. (Top 1000 Birth Names Statistics, 2014)