Answer
Resistivity is an intrinsic property of a particular substance, while resistance is a measure for a particular resistor, made of a particular substance, with particular dimensions (length and cross-section).
Work Step by Step
Resistance is measured in ohms, and expresses the ratio of voltage/current of a resistor.
$1\Omega=1V/1A$
A wire's resistance is affected by:
the material from which it is made, its length, L, and its cross-sectional area, A.
$R=\displaystyle \rho(\frac{l}{A})$
The resistance of a given material is described by its resistivity, $\rho$, measured in ohm-meters. It is an intrinsic property of the material, regardless of its dimensions.
A copper wire has less resistance than an iron one with the same dimensions, because of its lower resistivity.
