Pol (DNA polymerase) refers to a gene in retroviruses, or the protein produced by that gene.
Products of pol include:
Common to all retroviruses, this enzyme transcribes the viral RNA into double-stranded DNA.
This enzyme integrates the DNA produced by reverse transcriptase into the host's genome.
A protease is any enzyme that cuts proteins into segments. HIV's gag and pol genes do not produce their proteins in their final form, but as larger combination proteins; the specific protease used by HIV cleaves these into separate functional units. Protease inhibitor drugs block this step.