Related Clues:

• See 46 Across
• What P.O.'s handle
• Item in an env.
• Spam, say
• 8 1/2 x 11 in. size
• Delta, for one: Abbr.
• Use the USPS
• Vacationer's accumulation, perhaps
• Shipping box: Abbr.
• Epistle (abbr.)
• Copier paper size: Abbr.
• Legal alternative: Abbr.
• U.S.P.S. deliveries
• Letters in a box
• DHL unit