proof paper

11 LETTERS · STARTS WITH P

proof paper is a valid 11-letter word worth 19 points in Scrabble and 22 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

P3R1O1O1F4P3A1P3E1R1

3 + 1 + 1 + 1 + 4 + 0 + 3 + 1 + 3 + 1 + 1 =19 PTS

DOUBLE WORD → 38TRIPLE WORD → 57

MEANING

What does proof paper mean?