-jə(r) noun
Etymology: supercharge (I) + -er
: a device (as a blower, compressor, or pump) to increase the volume air charge of an internal-combustion engine over that which would normally be drawn in through the pumping action of the pistons and to compensate for the lower density of air in altitude operation of aircraft engines or the deficiency of air charge in high-speed automotive operation ; also : a similar device for increasing air pressure — see cabin supercharger