凹くぼみ

noun

hollow; cavity; dent; depression

Refers to a sunken or indented area on a surface, such as a dent in metal, a hollow in the ground, or a depression in a shape. Both くぼみ and へこみ are used, with へこみ often sounding more casual or physical.

• 車くるまのドアに小ちいさな凹くぼみができた。

  There's a small dent in the car door.