What is the famous meaning of the "S" shield?

What IS IT on the mind of this Very

Kryptonain, that relates to his big "S" symbol on his chest that we little humans find so SUPER POWERFUL?

Hello to all fans of the "S" Man out there,
 I just can't tell you how EXCITED for that blockbuster of the summer known as "MOS"because tonight, meaning early Friday morning, there will be a special screening as there is with all summer blockbusters.  As promised I won't tell you what the acronym stands for, till I see the movie myself. Today however we are going to be talking about something hinted at in the many trailers to the film itself. That being of course the very symbol seen here

, the Super Shield that is worn by the last son of Krypton better known as Superman to those of us known as humans on planet earth. In the trailer I'm talking about he is being questioned by a certain newspaper reporter named Lane as to what the symbol on his bulging chest stands for and he responses "It's NOT what you think?" by all meanings possible though we know it stands for strength, right? Okay I will tell you for as long as I have known of Clark Kent, I never really gave it much thought as to what the famous red diamond with a yellow center meant on his boyscout alter ego's blue tights meant! Now I'm NOT saying I did have my own speculation or speculations as to what it could be meaning wise........ but the really big thing I can recall is that in high school outside of it being most commonly known as super coolness I also saw it as Spirit in oneself. In fact it took me a little while this very morning but I did find these
,two respective school colors of our local high schools in Richland Washington. Can you if your a local Tri Citizen resident or were at one time, know which schools they are meant to pay homage to?