Gritted Substance Used for Smoothing Wood
Puzzle 7 of Groups of Three Easy Pack
Question is: Gritted Substance Used for Smoothing Wood
and the answer is: SANDPAPER
Word Meaning:
SANDPAPER — (uncountable) Strong paper coated with (traditionally) sand or (today) manufactured aluminum oxide, silicon carbide, or other abrasive material, used for smoothing and polishing.
Definitions from Wiktionary.