backing jointer

15 LETTERS · STARTS WITH B

backing jointer is a valid 15-letter word worth 30 points in Scrabble and 37 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

B3A1C3K5I1N1G2J8O1I1N1T1E1R1

3 + 1 + 3 + 5 + 1 + 1 + 2 + 0 + 8 + 1 + 1 + 1 + 1 + 1 + 1 =30 PTS

DOUBLE WORD → 60TRIPLE WORD → 90

MEANING

What does backing jointer mean?