often capitalized, often attributive
1
a : the 19th letter of the English alphabet
b : a graphic representation of this letter
c : a speech counterpart of orthographic s
2
: a graphic device for reproducing the letter s
3
: one designated s especially as the 19th in order or class
4
[abbreviation for satisfactory]
a : a grade rating a student's work as satisfactory
b : one graded or rated with an S
5
: something shaped like the letter S