Custom Segment
Beginner PronunciationEN/ˈkʌstəm ˈsɛɡmənt/
A custom segment is a user group you define yourself with your own conditions, as opposed to the ready-made groups a tool ships with.
Conditions can combine user properties, events performed and a time window, and the result is usually saved so later reports reuse the exact same definition. That saving is the main point: until the definition is locked in one place, each person builds active user differently and two reports with the same label return two different numbers. Clear naming and writing the conditions into the segment description are therefore part of the work, not paperwork.