Yes, fess is a Scrabble word!
...and is worth 7 points in Scrabble, and 7 points in Words with Friends
fess
Noun
1. (heraldry) an ordinary consisting of a broad horizontal band across a shield
2. A city in north central Morocco; religious center
What Scrabble words can I make with the letters in fess?
3 Letter Words
2 Letter Words