aperture
broaching
cavity
chasm
check
clearing
cleft
crack
disclosure
fenestra
fistula
fontanel
foramen
gap
gape
gat
gulf
hiatus
hole
hollow
inlet
interval
lacuna
laying open
leak
opening
opening up
outlet
passageway
pore
slot
space
split
stoma
throwing open
uncorking
unstopping
vent
yawn
passage
anus
aortic orifice
blastopore
cardia
cervix
cervix uteri
external orifice
fontanelle
introitus
mouth
naris
os
porta hepatis
pylorus
rima
soft spot
spiracle
urethral orifice
uterine cervix
canal
crevice
duct
flange
gland
incision
laceration
meatus
mucosa
nozzle
secretion
slit
sphincter
valve