Like with most things, computer speak has a language all its own. When you create a website you most likely will encounter a lot of new lingo, and while some of it actually makes a lot of sense there are some terms that may be a bit weird, even for the techy amongst us.
When you think of a white hat you may think of the Kentucky Derby or a Royal Wedding but in SEO speak it means the group of techniques that use the best practice, the ones that earn you all the gold stars and brownie points, the ones that do not use bad manipulations to gain traction or ranking, but those who do what they do to the best of their abilities, create wonderful content and follow all the rules.
Things like time on page is pretty self explanatory. There are actually people out there who analyze data like how long people spend on a certain site. They are timed and when they click out that data is collected. You typically want people to spend some time on your site, not just click in and out in three seconds.
A mirror allows you to see yourself every day, well a mirror site is the same principle, it's the same site at a different address. Sneaky.
Link bait is another term that makes a lot of sense, especially if you use social media a lot. Think of all those quizzes that start "only 10 percent of people can ace this quiz" and so you click and try to prove them wrong only to find the quiz is super easy and a five year old could have aced it. This is link bait. A page that is designed to attract incoming links. You click, they have done their job.
Now for a strange one - latent systematic indexing. What this means is that the search engine will index commonly associated words in a document or content. These are also known as long tail searches. This also lets you avoid keyword stuffing in a document as you can use similar words or words associated with your original keywords to get your point across.
What about code swapping? This is when people change the content of a site after they have achieved high rankings. This is dicey to do as the content may not be as informative or even interesting after the switch. It will eventually hurt the ranking.