What does a "session" in Google Analytics refer to?

In Google Analytics, a "session" is defined as a period of time during which a user actively interacts with a website. This concept encapsulates all the interactions that occur during a single visit, including page views, events, transactions, and any other activity performed by the user. A session typically ends after 30 minutes of inactivity or when the user returns to the site after a break in their activity.

This definition is critical because it helps website owners and marketers understand user engagement on their sites. By analyzing sessions, one can gauge how well the site retains users and how effectively it encourages them to explore content, complete conversions, or engage with features.

Other options, while related to user interaction, do not accurately define a session. For example, the complete history of website visits would imply tracking over a longer duration and multiple sessions, rather than focusing on a single session's activity. The number of pages visited refers to user behavior during a session but does not encapsulate the broader concept of interaction. A unique visitor is an important metric for assessing site traffic but does not correlate directly with session duration or activity. Hence, the definition of a session as a time-limited interaction period provides a precise metric for website performance analysis.