tourbillon
/tʊrˈbɪljən/
noun
- A device in a mechanical watch that rotates the escapement and balance wheel to counteract the effects of gravity and improve accuracy.
- He saved for years to buy a vintage timepiece with a tourbillon movement.
- Collectors prize watches with a tourbillon for their craftsmanship and precision.
- The luxury watch featured a tourbillon that could be seen through the transparent case back.