In marketing, a segment refers to a homogeneous group within a population of customers, prospects, or consumers. This group shares common characteristics that allow for the implementation of tailored marketing strategies, whether in terms of the products offered or the communication messages used. Unlike a one-off direct marketing campaign, a segment is generally stable over time.

The creation of segments relies on a segmentation approach based on specific criteria. It is essential that the segments thus defined be exclusive, meaning that an individual can normally belong to only one segment. Furthermore, these segments must be operational and targetable, implying that it must be possible to create them concretely and address each segment specifically.

Segmentation methods are constantly evolving, becoming increasingly sophisticated with the use of new practices. It is crucial that segments are well-defined to be effective. For example, a segment grouping dissatisfied customers would be difficult to manage operationally. To delve deeper into the concept of segment, it is interesting to examine the concept of marketing targeting.