axis
center
center of action
center of gravity
centroid
centrum
core
dead center
epicenter
heart
hub
kernel
marrow
medulla
metacenter
middle
nave
nub
nucleus
omphalos
pith
pivot
storm center
umbilicus
bellybutton
centre
midpoint
point
innie
outie
abdomen
armpit
buttock
chakra
clitoris
diaphragm
genitalia
groin
kidney
mideyebrow
midriff
nipple
pelvis
perineum
plexus
sacrum
scrotum
spleen
vulva
naval