C++14 is a version of the C++ programming language, officially released in December 2014. It builds upon the features introduced in C++11, enhancing the language with new capabilities and improvements. Key additions include relaxed constexpr restrictions, which allow more complex computations at compile time, and the introduction of binary literals for easier representation of binary numbers. This version also includes improvements to the standard library, such as the addition of std::make_unique for better memory management. Overall, C++14 aims to make programming more efficient and expressive while maintaining compatibility with existing C++ codebases.