vein of penis

NOUN
13 LETTERS · STARTS WITH V

vein of penis is a valid 13-letter word worth 19 points in Scrabble and 23 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
V4E1I1N1O1F4P3E1N1I1S1
4 + 1 + 1 + 1 + 0 + 1 + 4 + 0 + 3 + 1 + 1 + 1 + 1 =19 PTS
DOUBLE WORD → 38TRIPLE WORD → 57
MEANING

What does vein of penis mean?