Insulation

A material used to prevent or inhibit the conduction of heat, electricity, even sound. 

Examples: Electrical wires are coated with waterproof plastic or rubber coatings to protect against moisture or water, which can act as a good conductor.  

Building insulations are used to reduce the flow of thermal through walls to help maintain a uniform and comfortable temperature, and to reduce energy costs. It reduces heat loss or heat gain as a barrier between the inside of your home and the outside. There are three major types of home insulation: foam, fiberglass, and cellulose.  

Soundproofing, on the other hand, provides acoustic insulation or the reduction or elimination of sound intensity.