depends

Depends is the third-person singular present tense of the verb depend, meaning to be contingent on, determined by, or influenced by something else. In everyday language, phrases like "This outcome depends on the weather" express conditionality. The term is used across disciplines to describe relationships in which one element’s existence, value, or behavior is conditioned by another.

In logic and philosophy, dependence relations describe how properties or events are determined by others. In computing and software development, dependencies are components required for a program to operate. A dependency may be a library, framework, or other package that must be present for correct execution. The status of a component often determines whether dependent software can be installed or run.

Package management systems formalize dependencies with metadata. In Debian-based systems, the control file of a software package includes a Depends field that lists runtime dependencies, and the package manager ensures these packages are installed. Build systems may use Build-Depends for build-time requirements. Dependency specifications can be versioned (for example, libfoo (>= 1.2)) and may include alternatives. The dependency graph, which models which packages depend on which, can reveal issues such as circular dependencies or conflicts, posing challenges for distribution and maintenance.

Beyond software, dependency analysis appears in project planning, economics, and statistics, where outcomes are examined relative to influencing factors. The concept of dependence contrasts with independence, indicating whether a change in one element tends to produce a change in another.