Yes, sole is a Scrabble word!

Verb

1. Put a new sole on

Adjective

1. Not divided or shared with others

2. Being the only one; single and isolated from others

Noun

1. The underside of footwear or a golf club

2. Lean flesh of any of several flatfish

3. The underside of the foot

4. Right-eyed flatfish; many are valued as food; most common in warm seas especially European