As Webster 1913 would probably say.
The ability to be polarized.
In
chemistry, polarizability refers to the property of a substance to be polarized by an
electric field. Under a strong field, the
electrons on an
atom or
molecule may shift their relative density such that they align more in the field direction (like a weather vane aligning with the wind). As a result, all the
dipoles aligning cause an increase in the local electric field.
Polarizability is empirically defined as a constant that relates
dipole moment to external electric field:
p = k
E
Where
p is the dipole moment,
E is the field, and k is the polarizability.
This quantity is also related to the
dielectric constant of a medium. Polarizability affects the strength of
electrostatic interactions through space. If the environment has low polarizability (the lowest being
vacuum, as it has no charges to move), then
Coulomb's Law shows those electrostatic interactions will be the strongest. In highly polarizable media such as
water, charges can be screened by local dipole reorientation, resulting in weaker through-space interactions.
Capacitors are designed to have dielectrics with very low polarizability, in order to prevent conduction of charge from one plate to another. Dielectrics in capacitors also have the advantage that slight polarizability allows a greater accumulation of charge on the opposing plates, increasing the capacitance of the component.