What does Concho mean?

A metal ornament for use on clothing or accessories, typically stamped with a design or fitted with an inlaid jewel or stone.

Heddels explains Concho 

With Navajo and Mexican roots, Conchos are a charming, time-honored detail that are typically added to leather goods such as belts and wallets. Another use of the concho is as a button or fastener on a garment such as a shirt. A concho can be something as simple as a round of hammered metal, or feature complexities like engraved designs and inlaid stones.

Examples of a Concho

A Concho adorning a Corter Natural Leather Snap Wallet.

A concho used as a fastener on a Stevenson Overall Co. Jacket