Definition :
Build-measure-learn (BML) is a process of building a product, measuring consumer metrics and learning from them to better respond to customer needs and improve the product for the ultimate sustainability of the company.
BML generally relies on releasing a minimum viable product (MVP), one that satisfies market demands without going overboard on features that customers don’t want. After release of the MVP, customer feedback and metrics can be used to improve future versions of the product.
Further Reading :
Book: The Lean Startup by Eric Ries