Yes, small is a Scrabble word!

Adverb

1. On a small scale

Adjective

1. Limited or below average in number or quantity or magnitude or extent

2. Limited in size or scope

3. (of children and animals) young, immature

4. Slight or limited; especially in degree or intensity or scope

5. Low or inferior in station or quality

6. Lowercase

7. (of a voice) faint

8. Have fine or very small constituent particles

9. Not large but sufficient in size or amount

10. Made to seem smaller or less (especially in worth)

Noun

1. The slender part of the back

2. A garment size for a small person