LiveStats Definitions Question

I don't really get the definitions of hits, impressions, visitors, and distinct visits.
And I'm tryinng to reconcile the statistics

Reconciling PPC Visitors & Webstats
For instance, I send my PPC traffic to a start page and google says that they sent me 17,648 visitors in October. I should get that number on my webstats (livestats) report. But it reports that the landing page had 78,020 visitors who entered on that page. As far as I can tell, that page never shows up as the target page in any advertisements and it's built to not do well in search. So there are really only two ways to enter on that page.
1 - PPC - which explains 18K of 78K October visitors
2 - Repeat visitors who came to that page again because they bookmarked it. Is it possible that 60K visits were due to book marks in October? I think it's unlikely.

LiveStats reported that During the Month of October, 2006:

A total of 380,099 distinct visits were made to the site.
The average visit lasted 4 Minutes and 22 Seconds.
395 distinct web pages were viewed a total of 3,254,821 times.
The average visit contained 8.56 page views.
Total page views as entry pages were 341,614.
And that there were 15,384,957 hits.

Here's some questions.
- How do these stats relate to each other?
- Is a visit the same as a visitor?
- What constitutes a hit?
- Does an entry page hold the same meaning as a visit...hit...visitor?
- Are page views under Entry pages the same as "visitors entering"?
- Trying to reconcile referrers with total visitors suggests that the largest number of visitors bookmarked us. Which makes some sense since visitors tend to come back a few times while making up their mind and members visit many many times/month.