1. Having one barrel
   "most guns are single-barreled"
   - single-barrelled [US]

Antonym: double-barreled [US]

• old-age insurance
• old-age pension
• old-age pensioner
• old-fashionedness
• old-field toadflax
• old-hat
• old-line
• old-maid's bonnet
• old-maidish
• old-man-of-the-woods
• old-time
• old-womanish
• old-world
• olde worlde
• olden
• Oldenburg
• older
• Oldfield
• oldie
• oldish
• oldness
• oldster
• oldtimer
• Olduvai Gorge
• oldwench