Source : WordNet®

PID
     n : inflammation of the female pelvic organs (especially the
         Fallopian tubes) caused by infection by any of several
         microorganisms (chiefly gonococci and chlamydia);
         symptoms are abdominal pain and fever and foul-smelling
         vaginal discharge [syn: {pelvic inflammatory disease}]

Source : Free On-Line Dictionary of Computing

PID
     
        {process identifier}