combination piston

18 LETTERS · STARTS WITH C

combination piston is a valid 18-letter word worth 25 points in Scrabble and 32 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

C3O1M3B3I1N1A1T1I1O1N1P3I1S1T1O1N1

3 + 1 + 3 + 3 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 3 + 1 + 1 + 1 + 1 + 1 =25 PTS

DOUBLE WORD → 50TRIPLE WORD → 75

MEANING

What does combination piston mean?