eraser

Short definition from Wiktionary

Noun

1. 1
   One who erases.
2. 2
   An object used to erase or remove something written or drawn by a pen or a pencil.
3. 3
   An object used to erase something written either by chalk on a chalkboard, by a marker on a whiteboard, or by some other erasable implement; a chalkboard eraser, whiteboard eraser, etc.
4. 4
   An overwriter program used to prevent data recovery.