A sandbox is a secluded environment on a computer, where you can run untested code or malware to study the results without having any ill effects on the rest of your software. A virtual machine is the most commonly used example of a sandbox, since it emulates a complete computer, called a guest operating system, on the main machine (called the host) Microsoft Virtual-PC, VMWare, VirtualBox, The Chromium Projects and QEMU are well-known examples in no particular order.”]
Source: https://blog.malwarebytes.com/101/2013/02/sandbox-sensitivity/