noun
cat litter box; litter tray
Refers to the container or tray where a cat does its business, not the litter material itself.
新しい猫用トイレを買ってきた。
I bought a new litter box for the cat.
猫用トイレは毎日掃除してください。
Please clean the cat's litter box every day.
猫砂 refers specifically to the litter material (sand, pellets) placed inside the 猫用トイレ.
Compound of 猫 (cat), 用 (for), and トイレ (toilet). A straightforward modern term.