Sandbox/ˈsændbɑːks/ Definition 1 of 3Pro Tip 1/3Childhood Play Used to describe activities typical for young children's playtime. She bought her niece a shovel and pail for the sandbox. Pro Tip 2/3Limited Area A sandbox has boundaries, representing a controlled space for activity. The toddlers had fun within the confines of the small sandbox. Pro Tip 3/3Outdoor Creativity Reference to a space for imaginative play, often in outdoor settings. Look at the castle I made in the sandbox!