There are 4 types of segmentation:
Segmentation with an event scope
This type of segment allows you to limit the traffic analyzed to events (Example: I want to focus my analysis on quote validations).
Segmentation with a visit scope
Working on a set of visits corresponding to predefined criteria, over a given analysis period. (Example: visits from sponsored links).
Segmentation with a visitor scope
This segmentation is based on a cohort notion. A cohort is defined over a period N. It is composed of all visitors that have shared (at least once) the same visit experience during period N. (Example: visitors that came from a sponsored link last week).
All visits made by these visitors meeting these criteria (during at least one visit) will be taken into account during your analysis period.
Segmentation with a user scope
When the scope allows visitors to connect to a user account, it is possible to use the account ID (CRM ID) as a reconciliation criterion for the cohort.