serial printer

NOUN
14 LETTERS · STARTS WITH S

serial printer is a valid 14-letter word worth 15 points in Scrabble and 18 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
S1E1R1I1A1L1P3R1I1N1T1E1R1
1 + 1 + 1 + 1 + 1 + 1 + 0 + 3 + 1 + 1 + 1 + 1 + 1 + 1 =15 PTS
DOUBLE WORD → 30TRIPLE WORD → 45
MEANING

What does serial printer mean?