What is the meaning of symbol '|' in mathematics?

Question

I was reading a editorial for one problem and i came across one statement:

We only need to consider submatrices with side length $sz$ such that $sz\mid X$.

Link to full editorial

Can anyone tell me meaning of this statement.

Answer 1

In this case, it seems to mean "divides" (which is indeed a common use of the symbol). As in

We only need to consider submatrices with side length $sz$ such that $sz$ divides $X$.

As long as $sz$ isn't zero, it's the same as saying that the division $\frac X{sz}$ results in an integer. (The fact that $0$ divides $0$, but $\frac00$ is nonsensical makes the two statements not entirely equivalent in general.)