What does Sylvanus mean?
Sylvanus is an uncommon first name for males but a somewhat popular surname for both adults and children (#146011 out of 150436, Top 97%). (2000 U.S. Census)
Below is a charted comparison of the popularity of the boy name Sylvanus and affiliated names. Silvio is the only prominent related form of Sylvanus (#unlisted). Adoption of these boy names was at its highest during the years 1920-1929 (usage of 0.201%) and is now much less, with Silvio becoming less fashionable. (Top 1000 Birth Names Records, 2014)
A suggested similar baby name is Sylvan. Like Sylvanus, this name is not frequently used.