(law enforcement) Initialism of police department. / (electronics) Initialism of phase detector. / Initialism of public domain. / Initialism of peritoneal dialysis. / Initialism of penile duplication.

(Ireland) Initialism of Progressive Democrats, a former political party disbanded in 2008. / (Malaysia) Initialism of Port Dickson, a town and district.

(cartography) Initialism of position doubtful.

Initialism of polydioxanone. / (linguistics) Initialism of pet-directed speech.

plural of PD

(chemistry) Abbreviation of micro-pulling-down.

(psychology) Initialism of pervasive developmental disorder. / (chemistry) Initialism of paraphenylenediamine.

Initialism of protein data bank. / (US, politics) Initialism of President's Daily Briefing or President's Daily Brief or President's Daily Bulletin.

Initialism of Portable Document Format. A standard for representing electronic documents, allowing them to be transmitted and reproduced accurately with the same printed layout.

Initialism of Portable Document Format. A document in PDF format. / Alternative letter-case form of pdf (“probability density function”) / Abbreviation of people's defence force.