principal argument

18 LETTERS · STARTS WITH P

principal argument is a valid 18-letter word worth 26 points in Scrabble and 35 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

P3R1I1N1C3I1P3A1L1A1R1G2U1M3E1N1T1

3 + 1 + 1 + 1 + 3 + 1 + 3 + 1 + 1 + 0 + 1 + 1 + 2 + 1 + 3 + 1 + 1 + 1 =26 PTS

DOUBLE WORD → 52TRIPLE WORD → 78

MEANING

What does principal argument mean?