Generalization (machine learning)
A model’s ability to make correct predictions on new, previously unseen data. A model that can generalize is the opposite of a model that is overfitting.1
You train a model on the examples in the training set. Consequently, the model learns the peculiarities of the data in the training set. Generalization essentially asks whether your model can make good predictions on examples that are not in the training set.
To encourage generalization, regularization helps a model train less exactly to the peculiarities of the data in the training set.