Although pageviews are central to Google Analytics, the calculation of interaction metrics and limits in Google Analytics is based on a broader set of interactions.
A Google Analytics hit is defined as a pageview, a virtual pageview, an event, a social action, or an Ecommerce transaction. Unlike regular pageviews, the other types of interactions are not generated by the default Google Analytics tracking code but instead require special coding.
For calculating time metrics and bounce, Google Analytics treats all hits equally. For this reason, if a virtual pageview (from a PDF download, for example) or an event (from a video play) occurs during a single-page visit, that visit is not counted as a bounce (unless, in the case of the event, you have coded the event as non-interaction).
Google Analytics bases interaction limits on hits and not exclusively on pageviews. Google Analytics can capture up to 500 hits per visit and 10 million hits per month. (The monthly hit limit for Google Analytics Premium increases to 1 billion.)
Although hit does not appear anywhere in the Google Analytics interface, it’s an important concept for Google Analytics practitioners.