sandbox (Noun) — Mould consisting of a box with sand shaped to mould metal.
sandbox (Noun) — A plaything consisting of a pile of sand or a box filled with sand for children to play in.
sandbox (Noun) — (computing) an isolated environment in which a program can be run or tested, for example to prevent accidental damage to other parts of the system. ex. "In computer security, a sandbox is a security mechanism for separating running programs. It is often used to execute untested code, or untrusted programs"