China 
Africa 
- Photonic crystal sensor
- Photonic crystals
- Photonic integrated circuit
- Photonic metamaterial
- Photonic metamaterials
- Photonic molecules
- Photonic-crystal fiber
- Photons
- Photophobia
- Photophoresis
- Photophosphorylation
- Photopic vision
- Photopigments
- Photoplethysmogram
- Photoplethysmography
- Photopolymers
- Photoprotection
- Photoproteins
- Photorealistic
- Photoreceptor cells
- Photoreceptor proteins
- Photoredox catalysis
- Photorefractive effect
- Photoresist
- Photoresistor
- Photorespiration
- Photosensitive glass
- Photosensitivity
- Photosensitizers
- Photosphere
- Photostationary state
- Photostimulated luminescence
- Photostimulation
- Photosynthetic efficiency
- Photosynthetic pigments
- Photosystem I
- Photosystem II
- Phototaxis
- Photothermal effect
- Photothermal therapy
- Phototoxicity
- Phototransduction
- Phototropin
- Phototubes
- Photovoltaic
- Photovoltaic effect
- Photovoltaic system performance
- Photovoltaic systems
- Phrase chunking
- Phreatic
- Phreatic line
- Phreatic zone
- Phreatomagmatic
- Phreatomagmatic eruptions
- Phred
- Phred quality score
- Phrenic nerve
- Phthalaldehyde
- Phthalates
- Phthalic anhydride
- Phthalocyanine
- Phthalonitrile
- Phugoid
- Phycobilins
- Phycobiliprotein
- Phycobilisomes
- Phycocyanin
- Phycoerythrin
- Phycoerythrobilin
- Phyllite
- Phyllosphere
- Phylogenetic
- Phylogenetic profiling
- Phylogenetics
- Phylogeography
- Physical access
- Physical acoustics
- Physical address
- Physical computing
- Physical constants
- Physical design
- Physical examination
- Physical geodesy
- Physical geography
- Physical inactivity
- Physical layout
- Physical medicine and rehabilitation
- Physical metallurgy
- Physical optics
- Physical plant
- Physical quantity
- Physical schema
- Physical security
- Physical symbol system
- Physical test
- Physical unclonable function
- Physical urticaria
- Physical-to-virtual
- Physicians
- Physics engine
- Physics of computation
- Physics of failure
- Physiographic regions
- Physiological conditions
- Physiological cross-sectional area
- Physiology
- Physiome
- Physisorption
- Phytane
- Phytase
- Phytic acid
- Phytoalexins
- Phytochelatins
- Phytochemicals
- Phytochrome
- Phytoene desaturase
- Phytoene synthase
- Phytoestrogens
- Phytofluene
- Phytol
- Phytomining
- Phytoremediation
- Phytosome
- Phytosterols
- Phytotoxic
- Pi
- Pi bond
- Pia mater
- Piano wire
- Pica
- Picard's theorem
- Piceatannol
- Pichia kudriavzevii
- Pickering emulsion
- Picket fence
- Pickling
- Picloram
- Pico
- Picocell
- Picornavirus
- Picosecond
- Picrate
- Picric acid
- Picrite
- Pictograms
- Picture Archiving and Communication System
- Picture plane
- Pidgeon process
- Pie chart
- Piece goods