What does Si mean?
Si \si\ as a name for boys. Si's name origin is Hebrew, and Si means "to hear, listen; reputation". Si is a variation of Simon (Hebrew). Biblical: Simon was the name of two of the apostles. Scarce as a name for kids.
Si is an uncommon first name for males but a very popular last name for all people (#39223 out of 88799, Top 44%). (2000 U.S. Census)
Simon (#231 the previous year), Szymon, Simpson, Sim and Simeon are the popular varying forms of Si (#unlisted) listed in the Top 1000. Usage of these boy names was at its highest during 1880-1889 and has become significantly lower since, with the versions Simeon and Sim becoming less stylish. Simon (#231) is the most fashionable name for newborns in this list, with this name going through a rebound in usage. Below is a graphed comparison of the usage of Si and related names. (2014 Birth Statistics)