thirteenth chord

16 LETTERS · STARTS WITH T

thirteenth chord is a valid 16-letter word worth 27 points in Scrabble and 26 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

T1H4I1R1T1E1E1N1T1H4C3H4O1R1D2

1 + 4 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 4 + 0 + 3 + 4 + 1 + 1 + 2 =27 PTS

DOUBLE WORD → 54TRIPLE WORD → 81

MEANING

What does thirteenth chord mean?