What does Selwyn mean?
Selwyn is an uncommon first name for males but a very popular last name for both adults and children (#48963 out of 150436, Top 33%). (2000 U.S. Census)
The only popular alternative form of Selwyn (#unlisted) is Silvio. Adoption of these boy names was at its highest during 1920-1929 (usage of 0.201%) and has become significantly lower since, with Silvio becoming less fashionable. Below is a charted comparison of the usage of the boy name Selwyn and associated names. (Top 1000 Birth Names Records, 2014)