Yes, prove is a Scrabble word!

Verb

1. Be shown or be found to be

2. Establish the validity of something, as by an example, explanation or experiment

3. Provide evidence for

4. Prove formally; demonstrate by a mathematical, formal proof

5. Put to the test, as for its quality, or give experimental use to

6. Increase in volume

7. Cause to puff up with a leaven

8. Take a trial impression of

9. Obtain probate of