sandbox

Concise Oxford English Dictionary © 2008 Oxford University Press:
sandbox/ˈsandbɒks/

▶noun

• 1 a box containing sand, especially one on a train to hold sand for sprinkling on to slippery rails.

• 2 historical a perforated container for sprinkling sand on to wet ink to dry it.

• 3 N. Amer. a children's sandpit.