A waterproof bag for holding bathrooms items (soap and toothpaste etc.) when you are travelling.
1He stroked his cheeks and replaced the mirror in his sponge bag.
2I'd somehow overlooked the small hand mirror in my sponge bag.
3Salander took off her leather jacket and from the bathroom brought a jar of Tiger Balm from her sponge bag.
4The video equipment and her motorcycle were gone, as well as the bag with her extra clothes and her sponge bag.
5He took his shaving mirror from the sponge bag Kristina Tacker had embroidered with his initials and a childishly formed rose.
6"Why didn't yu' travel in a sponge bag?" inquired Scipio.