To understand what a Google Analytics segment is, it’s important to determine what a Market Segment is.
According to Wikipedia, a Market Segment or segmentation is “a process of dividing a heterogeneous market into relatively more homogenous segments based on certain parameters like geographics, demographics, psychographics and behaviour.”
In simple terms, market segmentation is the process of dividing a broad consumer or business market.
How does this apply to Google Analytics? The official Google documentation says that “a segment is a subset of your analytics data”.
For example, of your entire set of website visitors (users), one segment may be users from a particular country or city. Another segment may be users who purchase a particular line of products or who visit a specific part of your website.
A segment isolates users/sessions based on certain conditions to create a focused group from a larger population so that data can be easily analysed.
Discover more about segments in Google Analytics.