sandbox

noun

1. a box or receptacle for holding sand, especially one large enough for children to play in.
2. Computers. an environment in which software developers or editors can create and test new content, separate from other content in the project (often used attributively): sandbox web design; New features are tested and critiqued in the demo sandbox.

adjective

3. Digital Technology. noting or relating to a genre of video game with a nonlinear structure that allows players to roam freely.

noun

1. a container on a railway locomotive from which sand is released onto the rails to assist the traction
2. a box with sand shaped for moulding metal
3. a container of sand for small children to play in
4. computing a protected environment in which an untrusted program may be run without affecting other parts of the system

n.also sand-box, 1570s as an instrument to sprinkle sand, from sand (n.) + box (n.1). From 1680s as “a box holding sand;” 1891 as a low-sided sand pit for children’s play.