.net vs .net core

Hello , basically what title is asking . I was reading into some microsoft software and got curious about their technologies , and stumbled upon .net and .netcore, and for the love of me cannot understand the difference between other than they .netcore is cross-platform. Is .netcore the more preferred technology or some other factor , im so confused please help haha

.NET core is the cross-platform version of .NET, and doesn’t officially have desktop UI functionality, though there are third-party implementations. .NET 5 is coming out soon, it’s cross platform, and it will replace .NET core.

“other than” is doing a lot of work in this sentence. I don’t think you quite get how big of a deal being able to run .Net on Linux is.