"Stateful" refers to a system or application that maintains information about its current status or condition over time. This means that it can remember previous interactions or data, allowing for a more personalized and continuous experience. For example, a stateful web application can keep track of user sessions, preferences, and actions, making it easier for users to navigate and interact with the service. In contrast, a stateless system does not retain any information between requests. Each interaction is treated independently, which can simplify design but may require users to re-enter information or settings. Understanding the difference between stateful and stateless systems is crucial in fields like software development and networking.