Definition from Wiktionary, the free dictionary
armpiece (plural armpieces)
- A piece of armour that protects the arm,
- A decorative companion.
2004, Rique Johnson, Whispers from a Troubled Heart, page 120:
- Years of being his armpiece have taught her exactly how to handle this situation; she is suddenly sure of it.
2007, Jane Hamilton, When Madeline Was Young, page 116:
- Madeline was in on the routine, and shortly after Louise exited, the swain and his armpiece departed for their outing to Little's Music Shop.