indirect primary

16 LETTERS · STARTS WITH I

indirect primary is a valid 16-letter word worth 25 points in Scrabble and 28 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

I1N1D2I1R1E1C3T1P3R1I1M3A1R1Y4

1 + 1 + 2 + 1 + 1 + 1 + 3 + 1 + 0 + 3 + 1 + 1 + 3 + 1 + 1 + 4 =25 PTS

DOUBLE WORD → 50TRIPLE WORD → 75

MEANING

What does indirect primary mean?