dependency
also: dependency chain, dependency graph, package dependency, shared library dependency
A software library, package, or component that another program requires to function properly. Dependencies must be installed and available on the system before or alongside the program that needs them.
In Linux, a dependency is any external code or resource that a program relies on to run. When you install an application, its package manager checks for all required dependencies and either installs them automatically or alerts you to install them manually.
Dependencies can be libraries (like libc for C programs), other packages, or specific versions of tools. For example, a web browser might depend on libssl for encryption support and libpng for image handling.
Package managers like apt, yum, and pacman automate dependency resolution, preventing the common problem of "dependency hell" where conflicting version requirements make installation difficult. You can check dependencies using commands like ldd program_name for binary files or by examining package metadata with apt show package_name.