Yes, halo is a Scrabble word!
...and is worth 7 points in Scrabble, and 7 points in Words with Friends
halo
Noun
1. An indication of radiant light drawn around the head of a saint
2. A toroidal shape
3. A circle of light around the sun or moon
What Scrabble words can I make with the letters in halo?
3 Letter Words
2 Letter Words