What C# and .NET are — C# Language

C# is a language that compiles to intermediate language (IL), executed by the .NET runtime. The CLR provides JIT compilation, garbage collection, type safety, and exception handling, while the BCL offers core libraries like System, System.Collections, and System.Net.Http. CTS/CLS enable interop between C#, F#, and VB.NET. .NET Framework (Windows‑only), .NET Core (open‑source, cross‑platform), and .NET 5+ (unified, fastest) represent the evolution of the platform.