second detector

15 LETTERS · STARTS WITH S

second detector is a valid 15-letter word worth 20 points in Scrabble and 23 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

S1E1C3O1N1D2D2E1T1E1C3T1O1R1

1 + 1 + 3 + 1 + 1 + 2 + 0 + 2 + 1 + 1 + 1 + 3 + 1 + 1 + 1 =20 PTS

DOUBLE WORD → 40TRIPLE WORD → 60

MEANING

What does second detector mean?