Regression can have several meanings depending on the context in which it is used:
1. In statistics, regression refers to a statistical method used to analyze the relationship between two or more variables. It is used to predict the value of one variable based on the values of other variables.
2. In psychology, regression refers to a defense mechanism in which an individual reverts to an earlier stage of development in order to cope with stress or anxiety.
3. In biology, regression can refer to the process of the loss or reduction of a particular trait or feature in an organism over time.
4. In economics, regression can refer to a decline in economic activity or growth, often measured by a decrease in GDP or other economic indicators.
Overall, regression generally refers to a backward movement or decline from a previous state or level.