NuGet is a widely used package manager and online platform that enables developers to share, discover, and install reusable code libraries, known as 'packages,' for applications built on Microsoft’s .NET framework. By simplifying the process of integrating third-party or open-source components, NuGet helps developers save time, maintain consistency, and ensure their software uses the latest, most secure versions of dependencies. NuGet is integrated into popular development tools like Visual Studio, making it easy to manage and update packages within projects.