Answer:
Perhaps the most important adjective for ballerinas and princesses.
What is flat, usually square, and made from trees but isn't wood?
What has a spine, tail, and leash but isn't a dog?
It breathes fire in fairyยญ-tales
It moves around in circles. We see it as we turn. It keeps us always warm. Always alive and always dying, Across the sky we see it flying, But touch it and we burn.
If itโs information you seek, come and see me. If itโs pairs of letters you need, I have consecutively three. What am I?