lacuna (n.)
- alveolus
- antrum
- aperture
- armpit
- basin
- bowl
- breach
- break
- caesura
- cavity
- cessation
- chasm
- check
- clearance
- clearing
- cleft
- concavity
- crack
- crater
- crypt
- cup
- defalcation
- defect
- deficiency
- deficit
- depression
- dip
- disclosure
- discontinuity
- fenestra
- fissure
- fistula
- fold
- follicle
- fontanel
- foramen
- gap
- gape
- gat
- gulf
- hiatus
- hole
- hollow
- inlet
- interim
- intermission
- interruption
- interstice
- interval
- jump
- lack
- leak
- leap
- leeway
- letup
- lull
- margin
- need
- omission
- opening
- orifice
- outage
- outlet
- passageway
- pause
- pit
- pore
- room
- scoop
- shell
- shortage
- sink
- sinus
- slot
- socket
- space
- split
- stoma
- suspension
- trough
- ullage
- want
- yawn
