# Session

> A group of pageviews and events from one browser, ended by a period of inactivity or another rule.

Source: https://datacenter.so/glossary/session
Also called: visit.

A session groups what one browser did in one visit. GA4 ends a session after 30 minutes of inactivity by default, and you can change the timeout ([Google](https://support.google.com/analytics/answer/9191807)). GA4 also estimates session counts rather than counting each one exactly.

Other tools use other rules. Datacenter counts a visit as one visitor's day on a site. Comparing sessions across tools is only meaningful when you know both rules. See [visitors, sessions and pageviews](https://datacenter.so/guides/sessions-users-pageviews).

## Related terms

- https://datacenter.so/glossary/unique-visitor
- https://datacenter.so/glossary/pageview
- https://datacenter.so/glossary/bounce-rate