“A coordination entity constitutes a central metal atom or ion bonded to a fixed number of ions or molecules.”
“In a coordination entity, the atom/ion to which a fixed number of ions/groups are bound in a definite geometrical arrangement around it is called the central atom or ion.”
“The ions or molecules bound to the central atom/ion in the coordination entity are called ligands.”
An example of a Coordination complex is in which Iron is a central metal atom and water is ligands.