.Net is an open source developer platform, created by microsoft for building many types of application
.NET is a free, cross-platform, open source developer platform for building many different types of applications.
With .NET, you can use multiple languages, editors, and libraries to build for web, mobile, desktop, games, and IoT.
You can write .NET apps in C#, F#, or Visual Basic.
Whether you're working in C#, F#, or Visual Basic, your code will run natively on any compatible operating system. You can build many types of apps with .NET. Some are cross-platform, and some target a specific set of operating systems and devices.
.NET provides a standard set of base class libraries and APIs that are common to all .NET applications.
Each app model can also expose additional APIs that are specific to the operating systems it runs on, or the capabilities it provides. For example, ASP.NET is the cross-platform web framework that provides additional APIs for building web apps that run on Linux or Windows.
To extend functionality, Microsoft and others maintain a healthy .NET package ecosystem.
NuGet is a package manager built specifically for .NET that contains over 100,000 packages.