Yes, walls is a Scrabble word!

Verb

1. Surround with a wall in order to fortify

Noun

1. An architectural partition with a height and length greater than its thickness; used to divide or enclose an area or to support another structure

2. Anything that suggests a wall in structure or function or effect

3. (anatomy) a layer (a lining or membrane) that encloses a structure

4. A difficult or awkward situation

5. A vertical (or almost vertical) smooth rock face (as of a cave or mountain)

6. A layer of material that encloses space

7. A masonry fence (as around an estate or garden)

8. An embankment built around a space for defensive purposes