Product-market fit is a concept in entrepreneurship that refers to the stage at which a company's product or service aligns with the needs of a specific market and meets customer expectations. It is often considered an important milestone for startups, indicating they have identified a viable business model and are prepared to expand. Achieving product-market fit means that the product effectively addresses a problem or meets a need for its target audience, resulting in strong demand and customer satisfaction. This is typically demonstrated by metrics such as high customer retention rates, positive feedback, word-of-mouth referrals, and sustainable growth in sales.