In mathematics, statistics, finance, computer science, particularly in machine learning and inverse problems, regularization is the process of adding information in order to solve a well-posed problem or to prevent overfitting. Regularization applies to objective functions in ill-posed optimization problems.

Regularization is a common process in natural languages; regularized forms can replace loanword forms (such as with "cows" and "kine") or coexist with them (such as with " formulae " and " formulas " or " hepatitides " and " hepatitises "). Erroneous regularization is also called overregularization. In overregularization the regular ways of ...