fetus

/ˈfitəs/
noun
  1. An unborn or unhatched offspring of a mammal, especially a human, after the main organs and body parts have developed (usually after the eighth week of pregnancy in humans).
    • During the second trimester, the fetus begins to move and kick.
    • The doctor used an ultrasound to check the health of the fetus.
    • A healthy diet is important for the development of the fetus.