What exactly is a slug and how would I use it

Need help
1

So I get that it is a URL replacement and makes URLs easier to look at than the objects id …

but what about collisions etc?

What if I have multiple things with the same slug like this.

site.com/page/neato-thing

How do I email URLs with unique slugs that are human readable?

2

I believe bubble has an inbuilt duplicate checker.

I think it adds -1, -2, etc after a slug to keep it unique.