This help page describes how ‘Single page visits’ works as a metric. See the Single page visits dimension for more information.
The ‘Single page visits’ metric shows the number of visits where the Page dimension item contained only a single unique value for the entire visit. This metric is helpful in context of dimensions where you want to see short visits, but not have as stringent rules as Bounces.
This metric counts the number of visits where the ‘Page’ dimension item contained only a single unique value for the entire visit. If a visitor reloads the page or fires link tracking calls, it still counts as a single page visit. As soon as the Page dimension changes to a second unique value, the visit no longer qualifies as a single page visit.
See Single access for a comparison between metrics.