thorium series

14 LETTERS · STARTS WITH T

thorium series is a valid 14-letter word worth 18 points in Scrabble and 19 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

T1H4O1R1I1U1M3S1E1R1I1E1S1

1 + 4 + 1 + 1 + 1 + 1 + 3 + 0 + 1 + 1 + 1 + 1 + 1 + 1 =18 PTS

DOUBLE WORD → 36TRIPLE WORD → 54

MEANING

What does thorium series mean?