photoelectric cathode

21 LETTERS · STARTS WITH P

photoelectric cathode is a valid 21-letter word worth 35 points in Scrabble and 38 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

P3H4O1T1O1E1L1E1C3T1R1I1C3C3A1T1H4O1D2E1

3 + 4 + 1 + 1 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 1 + 3 + 0 + 3 + 1 + 1 + 4 + 1 + 2 + 1 =35 PTS

DOUBLE WORD → 70TRIPLE WORD → 105

MEANING

What does photoelectric cathode mean?