Yes, lis is a Scrabble word!
...and is worth 3 points in Scrabble, and 4 points in Words with Friends
lis
Noun
1. A soft silver-white univalent element of the alkali metal group; the lightest metal known; occurs in several minerals
2. Chinese distance measure; approximately 0.5 kilometers
What Scrabble words can I make with the letters in lis?
2 Letter Words