What symbol is this? $\mathscr{S}$ What symbol is this? $\mathscr{S}$ \mathscr{S}
I drew it on Detexify to find how to write in mathjax, but it doesn't tell  me what it is...
Context:

"...call the resulting polyhedron $\mathscr{S}.$"

I knew that it probably didn't have any specific mathematical meaning, but I was just wondering where it was from, like $\theta$ is from the Greek Alphabet.
 A: It's just an upper-case S in a "script" typeface.
This doesn't have any fixed meaning any more than $S$ does, but can mean whatever a writer decides to call by a capital script S. This meaning ought to be defined in whatever context you find it used.
If you give more of the context you have found the letter in, we might be able to make a more informed guess at what it means there.
If you needed to go to Detexify, it's also possible what what you're really looking at is $\varphi$ (\varphi), a lower-case Greek letter phi. This has a number of conventional meanings, but is also often used as "just a letter" that an author picks at random to represent something specific to the context.
A: That is a variation of the big 'S'. The symbol $\mathscr{S}$ is useful in math writings. For example, if $S$ is a nonempty set, then the symbol $\mathscr{S}$ is a convenient choice to denote a sigma-algebra over $S$. It is in this case also informative.
A: It is just simply an alphabet used to denote any value,set,vector or anything else. It is made in different font and nothing special in it.
