In business we refer to a sandbox as the area in which you play or conduct business. It consists of three things: your geographical boundaries, your products or services, and either your client description if you sell direct or your distribution channel if you sell there.
When determining your sandbox, one area of thought is to make sure that the sandbox you are playing in is capable of getting you to the goals you have created for yourself. Problems could include not having enough customers or not having the right customers in your geographical boundaries. The product or service may have saturated the market you’re in, and the client description could have changed or expanded.