S-Rank

Originally created in Japan where anything below grade ‘C’ is considered a failure. The 'S-Rank' gives way to a wider range of obtainable grades. Western developers soon realized that the ‘S-Rank’ was much cooler than the boring ‘A’. An A rank is commonly obtained by getting a 95% to 100%. If we are flawless or have a perfection in something, it would be an s (getting 100% or more than 100% usually by bonus).  Many people have wondered what the S stands for… Special? Super? No one knows for sure.

S ranks can be used in many things, but most commonly found in video games. They can be used in other places such as in agencies, military, or maybe in some schools. S is displayed to show a perfection or flawless in any case of a rank all the way from F- to S.    
 
Some games like Armored Core 4 even offer a double S Rank otherwise known as a SS Rank. This is for completing the entirety of the missions with an S Rank Grade.