Is eraser a word in the Scrabble Dictionary

Yes, eraser is playable

...and is worth 6 points.

Found in the following dictionaries

Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)

"Eraser" Definition

noun

One that erases, especially an implement, such as a piece of rubber or a pad of felt, used for erasing marks made by pencil or chalk.
One that .
A device (as a piece of rubber, or a felt pad) used to marks (as of ink or chalk).