serial number

13 LETTERS · STARTS WITH S

serial number is a valid 13-letter word worth 16 points in Scrabble and 21 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

S1E1R1I1A1L1N1U1M3B3E1R1

1 + 1 + 1 + 1 + 1 + 1 + 0 + 1 + 1 + 3 + 3 + 1 + 1 =16 PTS

DOUBLE WORD → 32TRIPLE WORD → 48

MEANING

What does serial number mean?