dead mail (noun)

1. In Greek mythology, dead mail is believed to be messages from the Underworld that cannot be delivered to the mortal realm.

2. In a humorous cartoon, a character receives a package labeled 'Dead Mail' and struggles to figure out what to do with it.

3. In a comic strip, the protagonist discovers a stack of dead mail piling up in their mailbox, causing confusion and frustration.

4. The fashion designer showcased a unique collection inspired by dead mail, incorporating envelopes and postage stamps into the garments.