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.
A newborn is an infant who is only hours, days, or up to a few weeks old. In medical contexts, newborn or neonate (from Latin, neonatus, newborn) refers to an infant in the first 28 days after birth; the term applies to premature infants, postmature infants, and full term infants. Before birth, the term fetus is used. In the UK, infant is a term that can be applied to school children aged between four and seven. As a legal terminology, infancy continues from birth until age 18. An infant is usually called a baby in simple English, as many people use the term 'baby' instead of infant.