Yes, gulf is a Scrabble word!
...and is worth 8 points in Scrabble, and 11 points in Words with Friends
gulf
Noun
1. An arm of a sea or ocean partly enclosed by land; larger than a bay
2. An unbridgeable disparity (as from a failure of understanding)
3. A deep wide chasm
What Scrabble words can I make with the letters in gulf?
3 Letter Words