Answer: The bond formation between two polar atoms.
Polarization has to do with how the electrons are being shared in a covalent bond. When two atoms with different electronegativities bond together, the valence electrons are unevenly shared between them. The more electronegative atom will pull the electrons of the bond closer to itslef because it has a strong "desire" for those electrons, thus making the bond polar.
Ex: HCF3 or trifluoromethane. The electrons between the carbon and fluorine reside closer to the fluorine because fluorine is more electronegative.
