back letter

11 LETTERS · STARTS WITH B

back letter is a valid 11-letter word worth 18 points in Scrabble and 21 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

B3A1C3K5L1E1T1T1E1R1

3 + 1 + 3 + 5 + 0 + 1 + 1 + 1 + 1 + 1 + 1 =18 PTS

DOUBLE WORD → 36TRIPLE WORD → 54

MEANING

What does back letter mean?