Difference between pump and compressor

The main difference is pump are used to transfer liquid from low-level head to high-level head while the compressor is used for gases to transform from low to much high pressure. Mechanically water is in-compressible so it can't be used in compressors. Let us have a deep insight into the difference between pump and compressor. 

Difference :

• The pump is a device which is used to increase the pressure of incompressible fluids like liquid fluids whereas the compressor is a device which is used to increase the pressure of compressible fluids like gaseous fluids.
• Pump has got more to do with the head at increased pressure but no significant change in temperature while the compressor has got more to do with the increased pressure and increased temperature.
• A pump used to move the fluid at any height from one location to another where the compressor increases the fuel pressure or potential energy.
• Pump increase pressure of the fluid by moving it at any height where the compressor increases the pressure of the fluid by compressing it.
• There is no change of volume from inlet to outlet in the pump and in compressor change in volume from inlet to outlet.
• A compressor has storage capacity while no storage capacity in a pump. 
• The pump is relatively cheaper as compared to the more expensive compressor. 

Basically, with a pump, both input and output are open to equal atmosphere, but with a compressor, we output into a regulated, fixed-volume container for deliberate disequilibrium (pressure).

The most important misunderstanding people have is between flow and Pressure.