PSD may refer to:
Science and engineering
- Particle size distribution
- Proportionalâ"summationâ"difference, type of PID controller
- Platform screen doors, on railway platforms
- Position sensitive device or detector, 2D photodetector
- Positive semidefinite A property of some matrices
- Postsynaptic density, a specialization of the cytoskeleton at the synaptic junction
- Power spectral density, distribution of power of a signal
Computers
- Personal or portable storage device
- .psd Photoshop document file extension
- Programmable system device, type of integrated circuit
- Professional Scrum Developer, a course leading to certification for Scrum (development)
Medicine
- Post-stroke depression
- Postsynaptic density
psd
Politics
- Parti social démocratique du Québec, a former provincial political party in Quebec, Canada
- Party of Socialists and Democrats, a major political party of San Marino
- Civil Movement "People's Self-Defense", a defunct political movement in Ukraine which was part of the Our Ukraineâ"People's Self-Defense Bloc electoral alliance
- Social Democratic Party (Albania), a minor political party of Albania
- Social Democratic Party (Angola), a political party of Angola
- Social Democratic Party (Benin), a political party of Benin
- Social Democratic Party (Brazil, 1945â"65), a defunct political party of Brazil
- Social Democratic Party (Brazil, 2011), a current political party of Brazil
- Social Democratic Party (El Salvador), a political party of El Salvador
- Social Democratic Party (France), a defunct political party of France
- Social Democratic Party (Mexico), a defunct political party of Mexico
- Social Democratic Party (Moldova), a political party of Moldova
- Social Democratic Party (Nicaragua), a political party of Nicaragua
- Social Democratic Party (Portugal), a major political party of Portugal
- Social Democratic Party (Romania), a major political party of Romania
- Social Democratic Party (Rwanda), a political party of Rwanda
- Social Democratic Party (Spain), a defunct political party of Spain
- Social Democratic Party (India), a political party of India
- Socialist Destourian Party, the old name (to 1988) of the ruling party in Tunisia, currently called Constitutional Democratic Rally
Finance
- Payment Services Directive, EU regulation for payment services
- Private Sector Development, term used in international development
Travel
- Port Said Airport, Egypt, IATA code
People
- PSD (rapper), a Californian rapper and hip-hop producer.
Education
- Philippine School Doha, a Filipino school in Doha, Qatar
- Pontiac School District, a school district in Michigan, US
- Poudre School District, a school district in Larimer County, Colorado
Others
- Pennsylvania Sumerian Dictionary
- Initials for Protective Services Detail, Personal Security Detachment, or Personal Security Detail, US military security details
- Pesticides Safety Directorate, UK
- Plains Indian Sign Language, US, ISO 639-3 code
- Prevention of Significant Deterioration (PSD) permit, Clean Air Act (United States)
- Program Service Data, data displayed on HD radio receiver
- Post Show Depression
- Presidential Study Directive, a kind of national security directive from the Obama presidency