In a didactic episode of Today I Found Out, host Simon Whistler explains why schools typically use a grading scale that begins at “A “and goes through “D”, but skips the “E” and goes straight to “F”. As it turns out, “F” stands for fail, nothing else.
Rather than a failure on the part of academic institutions to know the alphabet, the simple answer is that “F” stands for “fail.” The other four grades are more or less considered “passing” (though in some districts a D is also a failing grade), which is why they go in alphabetical order. The F is considered separate as it denotes a failing grade, and does not need to go in alphabetical order. It just so happens that “fail” starts with a letter that skips one letter alphabetically on the scale.