Many models of stationary reciprocating compressors (piston driven) have similar components.
Please see the image below for the names of the various parts used to build a compressor.
The compressor shown is model 2475, a two stage, electric unit with an 80 gallon air receiver tank.
Other models and option packages can have similar and/or different components. You can find a parts breakdown and operators manuals for other models at: www.irrecip.com/documents