Yes, sol is a Scrabble word!
...and is worth 3 points in Scrabble, and 4 points in Words with Friends
sol
Noun
1. A colloid that has a continuous liquid phase in which a solid is suspended in a liquid
2. (Roman mythology) ancient Roman god; personification of the sun; counterpart of Greek Helios
3. The syllable naming the fifth (dominant) note of any musical scale in solmization
What Scrabble words can I make with the letters in sol?
2 Letter Words