What is meant by the notation $\sim$

Question

I was looking at this question, I then was unsure what the exact definition of the notation $\sim$ in this answer

Answer 1

$f(x) \sim g(x)$ means $\lim\limits_{x \to \infty} \frac{f(x)}{g(x)} = 1$ and is called asymptotic equivalence.

Edit: by looking at the linked by OP answer, I can conclude the notation there means Asymptotic series.