lepton number

13 LETTERS · STARTS WITH L

lepton number is a valid 13-letter word worth 18 points in Scrabble and 25 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

L1E1P3T1O1N1N1U1M3B3E1R1

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

DOUBLE WORD → 36TRIPLE WORD → 54

MEANING

What does lepton number mean?