Originally created in Japan where anything below grade ‘C’ was considered a failure. The 'S-Rank' allowed for a wider range of obtainable grades and thus player motivation, meaning that it was soon adopted by western developers who realized that the ‘S-Rank’ was much cooler than the boring ‘A’. An A rank is commonly obtained by getting a 90% to 95%. If the player is flawless or achieves perfection in something, it qualifies as an S . Many people have wondered what the S stands for… Special? Super? No one knows for sure.
S ranks can be used in many areas but are most commonly found in video games although they are used in other places such as in certain governmental agencies, the military and in some schools.
Some games (e.g. Armored Core 4, Knights in the Nightmare...) even offer a double or triple S Rank otherwise known as an SSS Rank.