Annulus
- Annular blowout preventer
- Annular eclipse
- Annular lake
- Annular ligament (disambiguation)
- Annular tropical cyclone
- Annulation
- Annulet (disambiguation)
- Annulus (botany)
- Annulus (firestop)
- Annulus (mathematics)
- Annulus (mycology)
- Annulus (well)
- Annulus (zoology)
- Annulus of Zinn
- Anulus fibrosus disci intervertebralis
- Combustor
- Piston
- Ring (disambiguation)
- Ring (jewellery)