kitty litter UK /ˈkɪti ˈlɪtə(ɹ)/US /ˈkɪti ˈlɪtɚ/ noun3 •(informal) Any similar mix, used to soak up liquid spills. •Synonym of cat litter. •(informal) A gravel trap (a large area of gravel used to slow cars that leave the track) formskitty litters