Define resistance in terms of Ohm's Law.

V = I * R

where:

V = Voltage across the resistor (measured in volts, V)

I = Current passing through the resistor (measured in amperes, A)

R = Resistance of the resistor (measured in ohms, Ω)

In other words, the resistance of a component determines how much opposition it offers to the flow of electric current. Materials with higher resistance impede the flow of current more than materials with lower resistance for the same amount of voltage applied.