USPS SLANG GLOSSARY
Like many organizations, the US Postal Service has its own vocabulary of formal and slang terms. For example, envelopes that enter the automatic canceller back to front are called smiles if the flap makes a V and frowns if the flap is inverted. Others include:
Balloon: an unusually large sack or pouch of mail.
Bulkie; Heavy: a regular envelope containing an irregular object (e.g., a pen).
Chunk: a small parcel.
Dump up: to empty sacks for sorting.
Elbow and eyeball: to check empty mail sacks for trapped items.
Flagpole: overseas military post office.
Hit: to postmark mail by hand.
Hot mail: preferential mail.
Log; Truck: a heavy parcel.
Skin sack: a sack or pouch containing few items.
Skip: an item of mail that accidentally escapes machine cancellation.
Jane Austen (1775-1817)