Yes, bis is a Scrabble word!
...and is worth 5 points in Scrabble, and 6 points in Words with Friends
bis
Noun
1. A heavy brittle diamagnetic trivalent metallic element (resembles arsenic and antimony chemically); usually recovered as a by-product from ores of other metals
What Scrabble words can I make with the letters in bis?
3 Letter Words
2 Letter Words