Resistance is the property of a conductor, which determines the quantity of current that passes through it when a potential difference is applied across it.A resistor is a electrical componet with a predetermined electrical resistance, like 1 ohm, 10 ohms 100 ohms 10000 ohms etc.Depending on how much current you want to pass through a circuit, you would design the circuit with the required resistors.When it comes actual circuit designing, dealing with components or physical board designing, these two words become interchangeable.For example, if we say “a resistor of 22 ohms” or we say “a resistance of 22 ohms”, both are accpetable.