The majority class is the class label that appears most frequently in an imbalanced classification dataset. Models trained on such datasets may overemphasize the majority class unless imbalance is addressed through sampling, weighting, or evaluation design.
The more common label in a class-imbalanced dataset. For example, given a dataset containing 99% negative labels and 1% positive labels, the negative labels are the majority class. Contrast with minority class. See Datasets: Imbalanced datasets in Machine Learning Crash Course for more information.