On Superman's costume what does the S symbolize?

Superman, a superhero in a blue costume with a red cape and a famous "S" on his chest was created by writers Jerry Siegel and Joe Shuster. He first appeared in the first issue of Action Comics in 1933. "It's Superman, strange visitor from another planet, who came to Earth with powers and abilities far beyond those of mortal men." ('Adventures of Superman' 1952).

The 'S' on his chest is not a letter but rather a Kryptonian symbol meaning “hope” (or in later versions of the character) a symbol from the family crest of 'The House of El'. Superman was born on the fictional planet Krypton and was named Kal-El. He was sent off the planet by his parents as it was dying. He was found and adopted by farmers Jonathan and Martha Kent, who named him Clark Kent. He later became a reporter for 'The Daily Planet' newspaper where he met and fell in love with reporter Lois Lane. She dubbed the 'visitor from another planet', Superman.