Portugal's ISO country code

Periodic table

Polythiophene, a molecule

Physical therapy

Platinum, a chemical element

Porcupine Tree, a British progressive rock group.

PT boat, a type of small fast ship used by the US Navy in World War II

Mitochondrial permeability transition, a loss of impermeability of the membranes of mitochondria that occurs under some pathological conditions such as traumatic brain injury

Personal training

Prothrombin time, a measurement of blood coagulation

Partido dos Trabalhadores (Worker's Party), a Brazilian political party

Prequel trilogy, Episodes 1, 2, and 3 of the Star Wars series of movies

Part time work or study pattern

Perpetual traveler, Permanent Tourist, or Prior Taxpayer

Port, a facility for receiving ships and handling cargo

Point, a unit of measure used in typography

Panorama Tools

Pint, a unit of volume or capacity

Pacific Time zone

Phyllodes tumor

Patient, a medical abbreviation

Portugal Telecom

West Air Sweden IATA airline designator

Capital Cargo International Airlines IATA airline designator

Parti des travailleurs (Workers' Party), a French political party

Pulau Tiga, an island in South China Sea

pt is a measurement in the print industry for thickness of card stock.

Physical training, US military term for its exercise programs

Pararosaniline-toluidine histological stain.

a symbol for Peat in the Unified Soil Classification System

Petronas Towers,a pair of towers in Kuala Lampur,Malaysia

.pt the ccTLD for Portugal.

Portuguese language, in ISO 639 alpha-2

Priston Tale, an MMORPG based out of South Korea.

Pt is the symbol, in particle physics formulae, for the transverse momentum (the momentum that is transverse to the beamline of a particle detector)