PDA may refer to: Science and technology Patron-driven acquisition, a mechanism for libraries to purchase books Personal digital assistant, a mobile device Photodiode array, a type of detector Polydiacetylenes, a family of conducting polymers Pitch detection algorithm, to find the pitch of a signal Pushdown automaton, a type of abstract device in automata theory Biology and medicine Pancreatic ductal adenocarcinoma, the main type of pancreatic cancer Patent ductus arteriosus, a heart defect Posterior descending artery, an artery Potato dextrose agar, a microbiological media for culturing yeast and fungus Pathological demand avoidance Music "PDA" (song), a song by Interpol "PDA", a song by the Backstreet Boys from This Is Us "PDA", a song by Audio Adrenaline from Audio Adrenaline "P.D.A. (We Just Don't Care)", a song by John Legend "PDA", a song by Emily Burns Organizations Parenteral Drug Association, a global pharmaceutical trade association Pharmacists' Defence Association, UK Peruvian Debate Association, for inter-school debating Pinoy Dream Academy, the Philippine franchise of Endemol's Star Academy Population and Community Development Association, Thailand Private defense agency, an enterprise which would provide personal protection and military defense services to individuals Professional Driver Association, of NASCAR drivers before the 1969 Talladega 500 Public development authority, government-owned corporations in Washington, US Politics Alternative Democratic Pole, a political party in Colombia (Polo Democrático Alternativo) Progressive Democratic Alliance, a former political party in British Columbia, Canada Progressive Democrats of America, a progressive political organization Party of Democratic Action, a Bosniak party in Bosnia-Herzegovina Movement of Democratic Action, a political party in Bosnia-Herzegovina (Pokret demokratske akcije) Aruban Democratic Party, an Aruban political party (Partido Democrático Arubano) Law and culture Public display of affection, an act of physical intimacy in the view of others Pregnancy Discrimination Act, US "PDA" (The Office), an episode from the American television sitcom The Office Past Doctor Adventures, spin-off novels from the BBC's Doctor Who Pub Design Awards, UK Professional Development Award, offered by the Scottish Qualification Authority Pathological Demand Avoidance