1. The number of a letter box at the post office where mail is collected
   - post-office box number, PO box number, box number

Type of: mailing address

• half hatchet
• half hitch
• half mask
• half mile
• half nelson
• half note
• half page
• half pound
• half rest
• half sister
• half snipe
• half sole
• half step
• half title
• half track
• half volley
• half-and-half
• half-and-half dressing
• half-arsed
• half-assed
• half-baked
• half-blooded
• half-bound
• half-bred
• half-breed