Perhaps the word is most used in terms of electricity and heat. Materials are classified on the basis of their being either good or bad conductors of electricity and heat. Most metals are good conductors while non metals are bad conductors of both heat and electricity. Bad conductors are used to insulate and contain the flow of electricity all around us. Copper being an excellent conductor is most used in wires where as rubber a bad conductor is used to insulate the wires. Electrical conductivity refers to a measure of the ability of a material to conduct a current of electricity.
A synonym of conductivity is the word conduction.