index set

9 LETTERS · STARTS WITH I

index set is a valid 9-letter word worth 16 points in Scrabble and 17 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

I1N1D2E1X8S1E1T1

1 + 1 + 2 + 1 + 8 + 0 + 1 + 1 + 1 =16 PTS

DOUBLE WORD → 32TRIPLE WORD → 48

MEANING

What does index set mean?