Yes, ridden is a Scrabble word!

Verb

1. Sit and travel on the back of animal, usually while controlling its motions

2. Be carried or travel on or in a vehicle

3. Continue undisturbed and without interference

4. Move like a floating object

5. Harass with persistent criticism or carping

6. Be sustained or supported or borne

7. Have certain properties when driven

8. Be contingent on

9. Lie moored or anchored

10. Sit on and control a vehicle

11. Climb up on the body

12. Ride over, along, or through

13. Keep partially engaged by slightly depressing a pedal with the foot

14. Copulate with