"Build-Measure-Learn" is a fundamental process in the Lean Startup methodology, designed to help entrepreneurs develop products efficiently. It begins with building a minimum viable product (MVP) that includes only the essential features needed to test a hypothesis about a business idea. After the MVP is created, the next step is to measure its performance through user feedback and data analysis. This information helps entrepreneurs learn what works and what doesn’t, allowing them to make informed decisions for future iterations of the product, ultimately leading to better alignment with customer needs and market demands.