sandbox
noun [ C ] uk/ˈsænd.bɒks/ us/ˈsænd.bɑːks/
(BOX OF SAND)
US (UK sandpit)（供儿童玩的）沙坑，沙盒
a hole in the ground, or a box, filled with sand in which children can play
Dogs should be discouraged from toileting in areas frequented by children, such as sandboxes or playgrounds.
The kids who use the deluxe sandbox with tent will find it very entertaining playing with the sand.