Yes, limb is a Scrabble word!
...and is worth 8 points in Scrabble, and 11 points in Words with Friends
limb
Noun
1. One of the jointed appendages of an animal used for locomotion or grasping: arm; leg; wing; flipper
2. Any of the main branches arising from the trunk or a bough of a tree
3. (astronomy) the circumferential edge of the apparent disc of the sun or the moon or a planet
4. Either of the two halves of a bow from handle to tip
5. The graduated arc that is attached to an instrument for measuring angles
6. Any projection that is thought to resemble a human arm
What Scrabble words can I make with the letters in limb?
3 Letter Words
2 Letter Words