This field identifies the number of single-page visits to your site over the selected dimension. For example, if you apply this metric to the Ad Campaign dimension, it'll display the number of single-page visits to your site by users that reached your site via a particular ad campaign.
The percentage of single-page visits (i.e. visits in which the person left your site from the entrance page).
This field identified the number of times a user has clicked on your Ads.
This metric identifies the number of entrances to your site. It will always be equal to the number of visits when applied over your entire website. Thus, this metric is most useful when combined with particular content pages, at which point it will indicate the number of times a particular page served as an entrance to your site.
This metric identifies the number of exits from your site and, as with entrances, it will always be equal to the number of visits when applied over your entire website. Use this metric in combination with particular content pages in order to determine the number of times that particular page was the last one viewed by visitors.
The percentage of site exits that occurred from a page or set of pages.
The number of new visits by people who have never been to the site before.
Time on Page
This field indicates how long a visitor spent on a particular page or set of pages. It is calculated by subtracting the initial view time for a particular page from the initial view time for a subsequent page. Thus, this metric does not apply to exit pages for your site.
This field indicates the total number of pageviews for your site when applied over the selected dimension. For example, if you select this metric together with Request URI, it will return the number of page views over the returned result set for the Request URI for your report.
Time on Site
The time a visitor spends on your site.
The number of times your visitors have been to your site (unique sessions initiated by all your visitors). If a user is inactive on your site for 30 minutes or more, any future activity will be attributed to a new session. Users that leave your site and return within 30 minutes will be counted as part of the original session.
A user that visits your site. The initial session by a user during any given date range is considered to be an additional visit and an additional visitor. Any future sessions from the same user during the selected time period are counted as additional visits, but not as additional visitors.
The number of visits during which the specified page(s) was/were viewed at least once.
Total Unique Searches
The total number of times your site search was used. This excludes multiple searches on the same keyword during the same visit.
Visits with Search
The total number of visits where internal site search was used.
The number of times a visitor searched again immediately after performing a search.
Time after Search
Starting from the first use of internal search, time spent on site until either the session ended or until another search happened
The average number of pages visitors viewed after performing a search. This is calculated as Sum of all "search_depth" across all searches / ("search_transitions" + 1)
The number of searches a visitor made immediately before leaving the site.
If goals are configured, the total number of visitors who have completed the first goal step for this particular goal.
The number of goals completed by visitors.
If goals are configured, the total number of visitors who have completed all elements defined for this particular goal.
Total Goal Value
This is the total value used in Google Analytics' ROI calculations, and can be either a set value for the page, or a dynamic value pulled from your e-commerce receipt page.
If goals are configured, the total cumulative value for this particular goal. This definition applies for Goal1 - Goal4 Values.
Per Visit Goal Value
This is the value used in Google Analytics' ROI calculations per visit, and can be either a set value for the page, or a dynamic value pulled from your e-commerce receipt page.
Goal Conversion Rate
In the context of Campaign Tracking, the percentage of sessions on a site that result in a conversion goal being reached on that site.
Source: Google Analytics