Definition of natural disaster : a sudden and terrible event in nature (such as a hurricane, tornado, or flood) that usually results in serious damage and many deaths The earthquake was one of the worst natural disasters of this century.
Synthesis, Chemical. the planned production of complex compounds from simpler compounds based on a knowledge of the reactantsâ chemical structure and reactivity. Chemical synthesis usually implies a sequence of several chemical processes (steps). In the early period in the development of chemistry, chemical synthesis was carried out mainly for inorganic compounds and was fortuitous in nature.
tr.v. cheÂ·latÂ·ed, cheÂ·latÂ·ing, cheÂ·lates. 1. Chemistry To combine (a metal ion) with a chemical compound to form a ring. 2. Medicine To remove (a heavy metal, such as lead or mercury) from the bloodstream by means of a chelate, such as EDTA.cheâ²latÂ·aÂ·ble adj.. (Chemistry) chem a coordination compound in which a metal atom or ion is bound to a ligand at two or more points on the ligand, so as to form a heterocyclic ring containing a metal atom. adj. 2. (Zoology) zoology of or possessing chelae. 3. (Chemistry) chem of or denoting a chelate.