- arenaAn enclosed area, often outdoor, for the presentation of sporting events (sports arena) or other spectacular events; earthen area, often oval, specifically for rodeos (North America) or circular area for bullfights (especially Hispanic America).
- arenationA form of therapeutic bathing in hot sand.
- arenicoliteA wormhole or other burrowing tunnel preserved in sandstone or another rock.
- areniformof or resembling sand
- areniliticOf or pertaining to sandstone.
- areniteAny sedimentary rock with a grain size in the sand range on the Wentworth scale.
- areno-sand