Porcelain

Porcupine

Porifera

Porocephalida

Porous alumina

Porphyrin

Porphyroblast

Porphyry

Positive psychology

Positive train control

Positron

Positronium

Post-Paleozoic ecological complexity

Post-perovskite

Postglacial vegetation and climate

Postharvest treatments of fruit

Posttraumatic stress disorder

Postulate

Postural equilibrium

Potassium

Potato

Potato, sweet

Potential flow

Potentials

Potentiometer

Pottery

Pottiales

Poultry production

Poverty, stress, and cognitive functioning

Powder metallurgy

Powder mixing

Power

Power amplifier

Power factor

Power integrated circuits

Power line communication

Power plant

Power shovel

Power-factor meter

Poynting's vector

Prairie dog

Prairie restoration on the American Prairie Reserve

Praseodymium

Prasinophyceae

Preamplifier

Prebiotic organic synthesis

Precambrian

Precast and prestressed concrete

Precast concrete

Precast prestressed concrete pavement (PPCP)

Precedence effect (hearing)

Precession

Precession of equinoxes

Precious element resources

Precious stone

Precipitation (chemistry)

Precipitation (meteorology)

Precipitation measurement

Precipitin

Precipitin test

Precise earthquake location

Precision agriculture

Precision approach radar (PAR)

Precision mass measurements of exotic nuclei

Predator-prey interactions

Predatory behavior in bacteria

Predatory feline genes

Pregnancy

Pregnancy disorders

Prehistoric technology

Prehnite

Preimplantation genetic diagnosis and therapy

Prenatal diagnosis

Press fit

Pressure

Pressure measurement

Pressure seal

Pressure vessel

Pressure-gain combustion

Pressurized blast furnace

Prestressed concrete

Prevention of rhino poaching

Priapulida

Priapulida (penis worms): implications of embryonic development

Prilling

Primary cilia

Primate

Primate color vision

Primate communication

Primate conservation efforts

Primate origins

Primate visual signals

Prime mover

Primulales

Print compliance verification

Printable semiconductors for flexible electronics

Printed circuit board

Printing

Printing on demand

Prion