Yes, fills is a Scrabble word!

Verb

1. Make full, also in a metaphorical sense

2. Become full

3. Occupy the whole of

4. Assume, as of positions or roles

5. Fill or meet a want or need

6. Appoint someone to (a position or a job)

7. Eat until one is sated

8. Fill to satisfaction

9. Plug with a substance

Noun

1. A quantity sufficient to satisfy

2. Any material that fills a space or container