Sandbox · WebGlossary.info · Uncover Your Unknowns in Web Development

In computer security, a security mechanism for separating running programs, usually in an effort to mitigate system failures or software vulnerabilities from spreading. A sandbox is often used to execute untested or untrusted programs or code, possibly from unverified or untrusted third parties, suppliers, users, or websites, without risking harm to the host machine or operating system. A sandbox typically provides a tightly controlled set of resources for guest programs to run in, such as storage and memory scratch space. Network access, the ability to inspect the host system, or read from input devices are usually disallowed or heavily restricted. ← Wikipedia
In software development, a testing environment that isolates untested code changes and outright experimentation from the production environment or repository. ← Wikipedia