The plural form of the noun fetus is fetuses.
Fetuses
The plural word for embryo is embryos.
The fetus' umbilical cord. (Singular) The twin fetuses' mother. (Plural)
pixaxe is the singular version, pickaxes is the plural version.
The plural version of bat is bats.
The plural of googol is googols.
Suppers is the plural version of supper.
Cephalic Version
These.
ounce is the singular version and ounces is plural.
The plural of "glass" is "glasses."