.NET Framework vs .NET Core vs .NET Standard ?!?

I think get a grip on the latest trends only to learn that I’m still steps behind.  Thanks to Immo Landwerth for this clear article and cool tricks.  It’s ten months old but new to me.  😑

.NET Standard – Demystifying .NET Core and .NET Standard

“NET Standard is a specification. Each .NET Standard version defines the set of APIs that all .NET implementations must provide to conform to that version. You can think of it as yet-another .NET stack, except that you can’t build apps for it, only libraries. It’s the .NET implementation you should use for libraries that you want to reference from everywhere.”

Descriptions of .NET
Implementations
OS
Open Source
Purpose
.NET Framework
Windows
No
Used for building Windows desktop
applications
and ASP.NET Web apps running on IIS.
.NET Core
Windows, Linux, macOS
Yes
Used for building cross-platform console
apps
and ASP.NET Core Web apps and cloud
services.
Xamarin
iOS, Android, macOS
Yes
Used for building mobile applications for
iOS
and Android, as well as desktop apps for
macOS.
.NET Standard
N/A
Yes
Used for building libraries that can be
referenced
from all .NET implementations, such as
.NET Framework, .NET Core and Xamarin.