auxiliary power unit

20 LETTERS · STARTS WITH A

auxiliary power unit is a valid 20-letter word worth 33 points in Scrabble and 37 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

A1U1X8I1L1I1A1R1Y4P3O1W4E1R1U1N1I1T1

1 + 1 + 8 + 1 + 1 + 1 + 1 + 1 + 4 + 0 + 3 + 1 + 4 + 1 + 1 + 0 + 1 + 1 + 1 + 1 =33 PTS

DOUBLE WORD → 66TRIPLE WORD → 99

MEANING

What does auxiliary power unit mean?