Hybrid AI refers to a type of artificial intelligence system that uses both rule-based and machine learning-based methods. By combining the two approaches, a hybrid AI system can benefit from the strengths of each method. Rule-based systems are fast and reliable, while machine learning algorithms are flexible and can adapt to changing conditions. By using a hybrid AI system, the overall performance and accuracy can be improved compared to using a single AI approach. 

Hybrid AI is often used in areas such as customer service and language processing, where a combination of rule-based and machine learning methods is needed to provide a desired outcome: for for handling common and complex queries in customer support, making predictions based on medical data analyses, for targeting advertisements, etc.