Water is a transparent and nearly colorless chemical substance that is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen and two hydrogen atoms, that are connected by covalent bonds.
1. recently born; called also neonatal. 2. newborn infant. postmature newborn (post-term newborn) post-term infant. premature newborn (preterm newborn) preterm infant.
Neonatal Medicine (Neonate means a baby under four-weeks old). While most hospital paediatricians look after sick newborn babies in special care baby units, neonatologists specialise in the care of the sickest and most premature babies in neonatal intensive care units.