The symbol for resistance is R, it is measured in ohms \((\Omega )\). The symbol for current is I, it is measured in amperes \((A)\).
All conductors show some opposition to electric current. This opposition to current is called resistance. A good conductor has low resistance. A poor conductor, or insulator, has high resistance.
If you want to measure resistance and you know Ohm’s law, it seems like you have an easy answer, right? Feed a known current through the thing you want to measure and read the voltage required.