sandbox
n.a safe place to test new ideas or software without affecting the real world. It can also be a box filled with sand for children to play in.
n.a restricted environment where software can be executed safely without risking damage to the host system. In a broader sense, it refers to a space for open-ended experimentation or play.
“The developer tested the new code in a sandbox first.”
“Before launching the update to all users, the team ran the script in a sandbox to check for security vulnerabilities.”
“The game is designed as a digital sandbox, allowing players to manipulate the environment and create their own objectives rather than following a linear narrative.”
In computing, it is often used as a modifier before another noun, such as 'sandbox environment' or 'sandbox mode'.
From sand + box.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.