negative class

In binary classification, one class is termed positive and the other is termed negative. The positive class is the thing or event that the model is testing for and the negative class is the other possibility. For example: - The negative class in a medical test might be "not tumor." - The negative class in an email classification model might be "not spam." Contrast with positive class.

Practitioners refer to negative class when building, training, or evaluating machine learning systems. It appears in research papers, product documentation, and technical discussions about AI capabilities and limitations.