An eraser is an object used to remove marks from paper or other surfaces.
You might use an eraser at school to correct mistakes on your math homework. Just rub it gently over the wrong mark and it should disappear. You can also use erasers to clean up spills or smudges on your desk or table. If you're painting, you might use a big eraser to remove paint from a surface that's not supposed to be painted.
How common is "eraser"?
Word eraser is considered rare in modern English. It has a balanced usage among all categories: speech, fiction, newspapers and academic texts.
Definitions
noun
One who erases.
(Canada, US, Philippines) An object used to erase or remove something written or drawn by a pen or a pencil.
Example: I have worn out the eraser on this pencil.
(Canada, US, Philippines) 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.
(computing) An overwriter program used to prevent data recovery.