Wiktionary
alt. A box used to provide a soiling area for (usually) pet cats, generally filled with sand, clay chips, etc. n. A box used to provide a soiling area for (usually) pet cats, generally filled with sand, clay chips, etc.
WordNet
n. a receptacle for cat excrement
Usage examples of "cat box".
Nor did I go get a red/white cat of my own to film in a copy-cat box here at my place (as I'm sure you must be thinking) & I downloaded images from _your_ apartment.
Through the doorway into an apartment that smelted like overboiled cabbage and cat box and unfiltered foreign cigarettes, and they were ushered through a tiny hallway past several closed doors to the sitting room at the far end of the corridor, and were seated on a huge old horsehair sofa, disturbing an elderly gray cat in the process, who stretched, stood up, and walked, stiffly, to a distant part of the sofa, where he lay down, warily stared at each of them in turn, then closed one eye and went back to sleep.