A bezel is a piece that surrounds the coin (think of a washer for a bolt) and it's usually made of metal. The coin is dropped in to a hole in the bezel then "Pressed" to lock it in place. This can damage the coin's rims, flatten them out and sometimes leaves partial lettering. These are used for advertising or souvenirs sometimes called "Lucky Coins."
Your coin looks like it was in a bezel at one time and has fallen out or been removed.
"Shine, shine, a Roosevelt dime All the way to Baltimore and running out of time" - Tom Waits 'Clap Hands'