cavity (n.)
- abysm
- abyss
- alveolus
- antrum
- aperture
- armpit
- arroyo
- basin
- booth
- bowl
- box
- breach
- break
- canyon
- cell
- chamber
- chap
- chasm
- check
- chimney
- chink
- clearing
- cleft
- col
- compartment
- concavity
- crack
- cranny
- crater
- crevasse
- crevice
- crib
- crypt
- cup
- cut
- cwm
- deep
- defile
- dell
- depression
- depth
- dike
- dip
- disclosure
- ditch
- draw
- excavation
- fault
- fenestra
- fissure
- fistula
- flaw
- flume
- fold
- follicle
- fontanel
- foramen
- fracture
- furrow
- gap
- gape
- gash
- gat
- gorge
- groove
- gulch
- gulf
- gully
- hiatus
- hold
- hole
- hollow
- incision
- inlet
- interval
- joint
- lacuna
- leak
- manger
- moat
- notch
- nullah
- opening
- orifice
- outlet
- pass
- passage
- passageway
- pew
- pit
- pore
- ravine
- rent
- rift
- rime
- rupture
- scissure
- scoop
- seam
- shaft
- shell
- sink
- sinus
- slit
- slot
- socket
- space
- split
- stall
- stoma
- trench
- trough
- vacuity
- valley
- vault
- void
- wadi
- well
- yawn
