noun
diaper bag; nappy bag
A bag used by parents to carry baby supplies such as diapers, wipes, bottles, and a change of clothes. Wasei-eigo from English 'mother's bag'.
wasei-eigo (Japanese-coined English), from mother's bag
マザーズバッグにはおむつと着替えが入っている。
The diaper bag has diapers and a change of clothes in it.
出かける前にマザーズバッグをチェックした。
I checked the diaper bag before going out.