how come

8 LETTERS · STARTS WITH H

how come is a valid 8-letter word worth 17 points in Scrabble and 18 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
H4O1W4C3O1M3E1
4 + 1 + 4 + 0 + 3 + 1 + 3 + 1 =17 PTS
DOUBLE WORD → 34TRIPLE WORD → 51
MEANING

What does how come mean?

1