What is meant by the term viability in terms of a fetus?

Viability refers to the stage in fetal development when the fetus is capable of surviving independently outside the uterus. This is generally considered to be at around 24 weeks of gestation, when the fetus weighs around 500 grams and has developed sufficiently mature lungs to breathe on its own. However, viability can vary depending on individual factors such as the fetus's size and health, as well as the availability of medical care. Advances in medical technology have improved the chances of survival for premature infants born before 24 weeks, but these infants still face significant health risks.