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.
Definition of the Placenta. The placenta is a flattened circular organ in the uterus of pregnant mammals that nourishes and maintains the fetus through the umbilical cord. This cord is the main link from the fetus to the placenta. Through it, the placenta provides oxygen and nutrients to the growing baby and removes waste products.