What is a permalink and does it differ from a slug in any way within WordPress?
Permalink means permanent link
In WordPress, the term permalink stands for a permanent link.
As with any website, you can’t have two exact URLs with two different pages. Therefore, WordPress uses permalinks to determine each page, post and custom post type singles separately.
Slug vs Permalink?
A permalink is a full URL, including the domain. However, the slug is referred to everything after the domain.