Possible Clues:

• Clothing accessory, perhaps ... or what you can see in each of four groups of circles?
• A cowboy may sport a big one
• Accessory worn near the navel
• Accessory worn at the waist
• A cowboy may have a big one
• It may be big on a cowboy
• *Ornamental fastener
• Pants-accessory clasp
• A cowboy might have a big one