A static library is a collection of precompiled code that can be linked into a program during the build process. Unlike dynamic libraries, which are loaded at runtime, static libraries are integrated directly into the executable file. This means that all the necessary code from the library becomes part of the final program, making it self-contained. Static libraries are typically used to simplify code management and improve performance. They allow developers to reuse code without needing to distribute separate files. Common formats for static libraries include .lib in Windows and .a in Unix/Linux systems.