There are many different variations of Superman's symbol, esp. over the last couple of decades, or different age.
Most of the recent comics and the most popular rendition and meaning of Superman's symbol is obviously his family crest, and the symbol of the great Jor-EL from Krypton. In Birthright, it was more of the symbol of all of Krypton, and a symbol of hope. Some think that it means just that of his name : Superman.
Anyone read about a lesser known meaning of the way his symbol portrayed? I came across a story at how the Symbol actually means and is suppose to portray a 'snake.' Has everything to do with Jonathans side of the family and Jonathans ancestors used the symbol for their own crest that signified the family name and Jonathan passed it onto Clark for him to use for his costume. So, the "S" in this story, actually was supposed to signify a snake held by Jonathan's side of the family.
Anyone come across this, and know what issue or when it appeared? I'm thinkin' early Silver Age.