Slugs

In WordPress, if your blog is using permalinks, a slug refers to how the post or page title is directly translated into the tail end of the URL. By default every word of the title in all lowercase is separated by a dash character which can result in extremely long slugs and URLs.

Historical Usage of Slugs

The term slug has a historical basis in the printing industry. Only a few decades ago newspapers were actually printed from lead slugs which were a form of movable type that formed letters, words, and sentences as copy was typed on a typewriter like device. Lead was used because it was easier to recycle the slugs by melting the lead down than to manually separate the slugs.