A slug is a few words that describe a post or a page. Slugs are usually a URL friendly version of the post title (which has been automatically generated by WordPress), but a slug can be anything you like. Slugs are meant to be used with permalinks as they help describe what the content at the URL is.
Example post permalink: http://simplebyte.net/help/chef-website
The slug for that post is “chef-website“.
