Regression is very closely related to classification. 1 While classification is concerned with the prediction of discrete classes, regression is applied when the "class" to be predicted is made up of continuous numerical values. Linear regression is an example of a regression technique.
Matthew, Mayo. “Machine Learning Key Terms, Explained.” KDnuggets, KDnuggets, 10AD, 2016, https://www.kdnuggets.com/2016/05/machine-learning-key-terms-explained.html (1)