A URL slug is the human-readable part of a URL that identifies a specific page. For example, in /blog/how-to-make-a-mind-map, the slug is "how-to-make-a-mind-map". Good slugs are lowercase, use hyphens, and avoid stop words.

It depends on your SEO strategy. Shorter slugs without stop words (the, a, an, is) are often cleaner, but keeping them can make the slug more readable. There is no definitive SEO advantage either way.