Meaning and name origin
Si \si\ as a boy's name is of Hebrew origin, and the meaning of Si is "to hear, to be heard; reputation". Si is a variant of Simon (Hebrew); biblical: Simon was the name of two of the apostles, including Simon Peter.
Si is not a popular first name for males but a very popular surname or last name for all people (#39223 out of 88799, Top 44%) (2000 U.S. Census).
Displayed below is a comparison of the popularity of the boy name Si and its source form. The only popular variation form ranked in the Top 1000/100 is Simon (#231). (2014 statistics).