An air compressor is an air compression device that uses energy (e.g., electricity, diesel, or gasoline) to drive an engine, rotate the compressor housing, and convert air (usually 1-atmosphere, about 1-bar) into compressed air.
An air compressor is a device with which gas can be compressed. The air compressor is similar to a water pump. Most air compressors are reciprocating piston, rotary vane or screw compressors. Centrifugal compressors are very large applications.
Air compressors have a wider range of use and a wider range of applications. You'll see gas stations supplying compressed air to inflate your vehicle's tires, while your tire shop uses compressed air and air tools to remove tires.