I grew up (in China) with the symbol $S$ representing the area for a shape.
Some examples would be $S_{ABC}, S_{ABCD}$. Sometimes, for the area of a triangle, a triangle symbol is added, like: $S_{\triangle ABC}$.
However, it seems like that in the English-speaking world, the letter $A$ is more commonly used. Area - Wikipedia
Someone pointed to me that the usage of the letter $S$ in China was under the influence of the Soviet Union, which eventually traces back to the French word: "superficie".
However, I do not speak French so that I can neither confirm nor deny this.
I am wondering which symbol is more commonly used worldwide. It is appreciated if you could share with me some of your knowledge about the symbold of area.