What does the "or" symbol mean as in "$ d\mid a$"

Question

What does the "or" symbol mean as in the following post:

How to prove $\gcd(a,\gcd(b, c)) = \gcd(\gcd(a, b), c)$?

In particular, the symbol is used in the above linked post in the following definition of $\gcd(a, b)$:

Given integers $a$ and $b$, there is one and only one number $d$ with the following properties.

1. $d \geq 0$
2. $d\mid a$ and $d\mid b$
3. $e\mid a$ and $e\mid b$ implies $e\mid d$.

Answer 1

In this context, you write $a|b$ to mean that $a$ divides $b$, or equivalently, that there is an integer $m$ such that $b=ma$.

See the article Divisor on Wikipedia, and also Vertical bar for other uses of this symbol.

Answer 2

you mean $d|a$. It is not 'or' symbol. It means d divides a.