Pol refers to a gene in retrovirus

Retrovirus

A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA...

es, or the protein produced by that gene.

Products of pol include:

Reverse transcriptase

Common to all retroviruses, this enzyme transcribes the viral RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 into double-stranded DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

.

Integrase

This enzyme integrates the DNA produced by reverse transcriptase into the host's genome.

Protease

A protease

Protease

A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....

 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.