Ionic bond: it is also called "electrovalent bond". It is "a type of chemical bond that can often form between metal and non-metal ions through electrostatic attraction";
Covalent bond is a form of chemical bonding, "characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds";
Metallic bond: "the chemical bond, which is characteristic of metals, in which mobile valence electrons are shared among atoms in a usually stable crystalline".
For additional information, go to google "ionic bond", "covalent bond" and "metallic bond" (my sources).