1. A large bag used by postal services to collect, transport, and deliver mail and parcels
The mail carrier emptied the mailbag at the post office.
O carteiro esvaziou o saco postal na agência de correios.
2. A sturdy canvas or fabric bag with a postal service seal or marking
The postal worker tied up the mailbag before shipping it to the central distribution center.
O funcionário dos correios amarrou o saco postal antes de enviá-lo para o centro de distribuição.