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
"After ignoring her lower back pain for too long, she was finally diagnosed with a severe case of PID that required immediate antibiotic treatment."
Initialism of pelvic inflammatory disease.
"The doctor explained that PID stands for a serious infection of the female reproductive organs known as pelvic inflammatory disease."
In plain English: A PID is an old-fashioned way to refer to a process ID, which acts as a unique number used by computers to track and manage running programs or tasks.
"The store manager decided to give his old car a quick pid before selling it."