periodical index

16 LETTERS · STARTS WITH P

periodical index is a valid 16-letter word worth 28 points in Scrabble and 32 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

P3E1R1I1O1D2I1C3A1L1I1N1D2E1X8

3 + 1 + 1 + 1 + 1 + 2 + 1 + 3 + 1 + 1 + 0 + 1 + 1 + 2 + 1 + 8 =28 PTS

DOUBLE WORD → 56TRIPLE WORD → 84

MEANING

What does periodical index mean?