noun
uterus
YOO-tur-us/ˈjuːtərəs/
The female reproductive organ in which a baby develops during pregnancy.
The anatomical model shows a fetus within the uterus.

Etymology
Latin uterus could mean either “womb” or “belly.” The English anatomical term preserves the specific womb meaning: the organ where a fetus develops.
In context
Treponema pallidum infects the baby either in the uterus or while the baby exits through the vagina at birth