bezel

1. The sloping edge or face on a cutting tool.
2. The oblique side or face of a cut gem; especially the upper faceted portion of a brilliant (diamond), which projects from its setting.
3. The rim and flange which encompasses and fastens a jewel or other object, such as the crystal of a watch, in the cavity in which it is set.
4. A formed external frame or cover affixed to a device for protective or aesthetic purpose · Modern smartphones have very thin bezels.

الجمع bezels