Churn refers to the rate at which customers or users stop using a product or service. In the context of product management, churn is a key metric that measures the number or percentage of users who cancel their subscription or stop using your software. High churn can be a red flag, indicating that your product may not be meeting the needs or expectations of your customers. It's important for product managers to understand and analyze churn to identify patterns, gather user feedback, and implement strategies to reduce churn and retain customers.