An absolute unique visitor is counted only once in the specified date range. For example, if I visit your site on Monday and again on Friday and you select a date range between Monday and Thursday, I will only be counted once as a visitor. If you select a date range between Monday and Friday, I again will only be counted once. This is important information about your site as it gives you an idea of how many new people your site is reaching for a specified date range.
Stickiness gives you an idea of how engaging your site is by how many visitors view more than one page. If I visit your site and never look at a second page, then my stickiness for that visit is 0% meaning I didn't engage or "stick" to your site. If I visit your site and look at a second page, then my stickiness is 100% meaning I did visit more than one page.
Bounce Rate is the opposite of Stickiness. Bounce Rate gives you an idea of how un-engaging your site is by how many visitors don't view more than one page. If I visit your site then leave without clicking another page, then my bounce rate is 100% meaning I left or "bounced". If I visit your site and do visit a second page, then my bounce rate is 0% meaning I engaged with your site.
Visitor Recency tracks how many days have passed since a visitor last visited your site. This information helps you monitor if your site brings visitors back to your site after 1 day through to 30+ days.
Average Visit Depth shows you the average number of pages viewed by each visitor per visit.
