CMake
In plain terms
A cross-platform build-system generator.
Going deeper
CMake generates native build files (Makefiles, Visual Studio projects) from a platform-independent configuration, easing cross-platform C/C++ builds. It abstracts over build systems.
Under the hood
CMakeLists.txt describes the build; widely adopted for portable C/C++ projects.
Examples
C/C++ projects, cross-platform builds, CMakeLists.txt, native toolchains.
Think of it like...
Like a universal translator producing the right build instructions for each platform.