environment variable
Computing term for a dynamic-named value that can affect the way running processes will behave on a computer.
Add a directory to the PATH environment variable.
This program reads environment variables to change its settings.
システム変数 (system variable) is a broader term that can include environment variables but also refers to variables set at the system level, not necessarily passed to processes.
Compound of 環境 (environment) and 変数 (variable), a direct calque from English 'environment variable'.