PDE may refer to:
Mathematics
- Partial differential equation, differential equation involving partial derivatives (of a function of multiple variables)
Life sciences
- Phosphodiesterase, enzyme important in intracellular communication
- Pug dog encephalitis
Organizations
- The European Democratic Party (esp. in Spanish, French or Italian languages)
- The Pennsylvania Department of Education
Technology and engineering
- Program development environment
- Pulse detonation engine, proposed substitute to the traditional jet engine <!-- does this differ from an engine of a pulsejet? -->
Philosophy
- Principle of double effect
Places
- Punta del Este
Other modes of abbreviation
- Polydichloric euthimal, fictional substance <!-- in a fraud? in a titled work? -->
- Pde (or Pde.), "Parade" (when serving as part of the proper name of a street or other way)
- Present Day English
- Preliminary Determination of Epicenters, the final earthquake bulletin of the National Earthquake Information Center (NEIC)
