The term 'unborn baby' is often used to refer to a FOETUS, which is an unborn child in the early stages of development. A FOETUS is typically defined as a human being from the moment of conception until the end of the eighth week of gestation. During this time, the FOETUS is growing and developing in the mother's womb. The term 'unborn baby' is often used to refer to a FOETUS in the later stages of development, when it is more developed and can be seen on ultrasound scans.