Yes, aqua is a Scrabble word!
...and is worth 13 points in Scrabble, and 14 points in Words with Friends
aqua
Noun
1. A shade of blue tinged with green
What Scrabble words can I make with the letters in aqua?
3 Letter Words
2 Letter Words
Noun
1. A shade of blue tinged with green
3 Letter Words
2 Letter Words