The C++ Standard Library provides an extensible framework, and contains components for: language support, diagnostics, general utilities, strings, locales, containers, iterators, algorithms, numerics, and input/output.

That's a common meaning of those words, i haven't ever seen another definition of it, and C++ itself defines it as this: The C++ Standard Library and C Standard Library are the libraries that the C++ and C Standard define that is provided to C++ and C programs to use.