fetus
Meaning of fetus: A fetus is the developing human organism from the end of the embryonic period until birth, distinct from the earlier embryo stage.
Definition of fetus
A fetus is the term used for a developing human organism from the end of the embryonic period, once the basic body structures and organs have begun to form, until birth. Before this point, the same developing organism is called an embryo, a distinction reflecting a shift from the initial formation of body structures to their continued growth and maturation.
During the fetal period, organs and body systems established earlier continue to grow, mature, and become capable of functioning outside the uterus, a process that continues throughout the remainder of pregnancy. Growth during this period is generally monitored through periodic prenatal visits and imaging.
The distinction between an embryo and a fetus is based on developmental stage rather than a difference in the organism's basic identity, and both terms describe different points along the same continuous process of prenatal development leading to birth.
Used in a sentence
Ultrasound was performed to assess fetal growth during the pregnancy.
Good to know
The terms embryo and fetus describe different stages of the same ongoing development rather than two different kinds of organism, with the changeover marking the point when major body structures have already formed.
Word origin
Where “fetus” comes from
From Latin fetus, meaning offspring or the bearing of young.