Related Clues:

• Send Liberal down in African country
• Word after "snail" or "chain"
• It may be junk – or first class?
• Knight's armor
• Parcels man mentioned
• Vote by __
• Preinstalled Apple app with an envelope icon
• What the postal service delivers
• It's always delivered in the same box
• Dating profile abbr. whose middle letter stands for "term"
• Missives: Abbr
• Put in the post
• P.O. Box filler