Uterus

The uterus is the medical term for the womb. It is the Latin word for womb. It is about the size and shape of an inverted pear. The uterus sits quite low in the abdomen and is held in position by muscles, ligaments and fibrous tissues. The uterus is joined to the vagina by the cervix that is also called the neck of the womb.

Source: https://www.news-medical.net/health/What-Does-the-Uterus-Do.aspx

During pregnancy the lining of your uterus thickens and its blood vessels enlarge to provide nourishment to the fetus. As pregnancy progresses, your uterus expands to make room for the growing fetus. By the time your baby is born, your uterus will have expanded to many times its normal size.

Source: https://www.acog.org/patient-resources/faqs/pregnancy/how-your-fetus-grows-during-pregnancy