PID or Pid may refer to: Medicine Pelvic inflammatory disease or pelvic inflammatory disorder, an infection of the upper part of the female reproductive system Primary immune deficiency, disorders in which part of the body's immune system is missing or does not function properly Prolapsed intervertebral disc, commonly called a herniated disc Science, technology and engineering BBC Programme Identifier, a unique identifier for a BBC television or radio programme brand, a season or series, or an individual episode OBD-II PIDs (on-board diagnostics parameter IDs), requests for data through an OBD connector in automotive repair Packet Identifier, a field in a MPEG transport stream packet Passive infrared detector, a passive infrared sensor Persistent identifier, a long-lasting reference to a document, file, web page, or other object Phosphotyrosine-interacting domain, also known as phosphotyrosine-binding domain, a protein domain which bind to phosphotyrosine Photoionization detector, measures volatile organic compounds and other gases Physical Interface Device, a class of a USB device PID controller (proportional-integral-derivative controller), a control concept used in automation Piping and instrumentation diagram (P&ID), a diagram in the process industry which shows the piping of the process flow etc. Principal ideal domain, an algebraic structure Process identifier, a number used by many operating systems to identify a process Organisations Police Intelligence Department, a staff department of the Singapore Police Force Political Intelligence Department (disambiguation), multiple organisations Politieke Inlichtingen Dienst (Political Intelligence Department), was the main security agency for the Dutch East Indies Prague Integrated Transport (Pražská integrovaná doprava – PID in Czech), an integrated public transport system in Prague Other uses Pathways into Darkness, a 1993 video game by Bungie "Paul is dead", a 1960s urban legend that Paul McCartney was dead Pid (video game), a 2012 video game by Might and Delight Project Initiation Documentation, in project management Party identification, the political party with which an individual identifies Everett Pid Purdy (1904–1951), American athlete who played in both Major League Baseball and the National Football League See also PIDS (disambiguation)