A recommendation engine is the definition of a system that receives data of user preferences and behaviors, and then analyzes them, then suggests relevant products, services, or content. These engines use advanced algorithms and machine learning techniques to make personalized recommendations that are tailored to an individual's interests and habits. By providing users with personalized suggestions, recommendation engines can enhance the user experience, increase engagement, and drive sales or conversions for businesses. Recommendation engines are commonly used in e-commerce, streaming platforms, social media, and other applications where personalization is a key feature.