source material

15 LETTERS · STARTS WITH S

source material is a valid 15-letter word worth 18 points in Scrabble and 22 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

S1O1U1R1C3E1M3A1T1E1R1I1A1L1

1 + 1 + 1 + 1 + 3 + 1 + 0 + 3 + 1 + 1 + 1 + 1 + 1 + 1 + 1 =18 PTS

DOUBLE WORD → 36TRIPLE WORD → 54

MEANING

What does source material mean?